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Making exceptional symmetries of SUGRA manifest

I found at least two hep-th papers interesting today. Nathan Berkovits brings us some field redefinition that maps his pure spinor formalism to the RNS formalism, using a new method of "dynamical twisting". My understanding is that it's not sufficient to understand why the calculated amplitudes agree. But I will only discuss

Exceptional Field Theory I: \(E_{6(6)}\) covariant Form of M-Theory and Type IIB by Olaf Hohm and Henning Samtleben.
The names may sound German to you but it's technically a French-American collaboration. ;-) I don't know the authors but I know all 4 people thanked in the acknowledgements, Liu, Nicolai, Taylor, and Zwiebach.

Supergravity (or M-theory) compactified on tori produces lower-dimensional theories with non-compact exceptional continuous (or discrete) symmetries (called the U-duality group in the M-theory case). Exceptional groups are sexy and mysterious, too.

It has always been plausible that a decent understanding of the origin of these exceptional symmetries could provide us with a new, spectacularly clear view into string theory's deepest inner workings. It could be just a straightforward technical result without far-reaching implications, too. We can't know for sure.

Formulations that make duality symmetries of string/M-theory manifest became popular in recent years.

In the case of T-duality, the part of the full U-duality group that is visible at every order of the weak coupling expansion of string theory, the paradigm carries the name "Double Field Theory" or "DFT". Both the circular compact coordinates and their T-dual partners are included as fields. It would be wrong to simply double-count so some constraint has to be added.

The new paper extends these techniques to M-theory, beyond the perturbative stringy expansions, where the exceptional symmetries occur. The ordinary well-known exceptional symmetries appear on the compactification of M-theory on \(T^k\) for \(k=6,7,8\) where the noncompact symmetries are \(E_{k(k)}(\RR)\) and U-duality groups are \(E_{k(k)}(\ZZ)\). In this paper, they discuss the \(k=6\) case.

Note that the supergravity has six compact periodic dimensions but the smallest nontrivial representation of the \(E_6\)-like group is \(27\)-dimensional. So to make this group manifest, we clearly need to add \(27\) compact dimensions (aside from the \(4+1\) noncompact ones) and not just \(6\) of them.

The would-be SUGRA theory would have too many degrees of freedom. Most of them are removed again by the following clever \(E_6\)-covariant constraint involving a cubic symmetric tensor invariant of the group \(d^{MNP}\):\[

d^{MNK} \partial_N\partial_K A = 0, \quad
d^{MNK} \partial_N A \partial_K B = 0

\] which should hold for all fields \(A\) or \(A,B\) in our \(5+27\)-dimensional spacetime. The bosonic SUGRA fields that live in this extended spacetime are the ordinary fünfbein \(e_\mu^a\) that remembers the metric in the five noncompact dimensions; \({\mathcal M}_{MN}\) which are the usual scalars in this supergravity living in the \(E_{6(6)}/USp(8)\) coset; \(A_\mu^M\) gauge fields which sort of remember the mixed compact-noncompact components of the metric in the Kaluza-Klein way; and \(B_{\mu\nu,M}\) which are the newest fields of the "EFT", or "exceptional field theory", namely some new tensor gauge fields.

The constraint generalizes (and was constructed by analogy from) the "strong constraint" in DFT which is a stronger version of \(L_0=\tilde L_0\) needed when the T-dual coordinates are added.

The action for these bosonic fields in the \(32\)-dimensional spacetime is kind of natural. I said that \(B\) were tensor gauge fields so there is a new gauge symmetry for them which doesn't use the ordinary Lie brackets like Lie algebras do. Instead, it uses the E-brackets (equation 2.15). The commutator of gauge transformations dependent on parameter fields \(\Lambda_{1},\Lambda_{2}\) is proportional to \(\Lambda\partial \Lambda\) structures, perhaps with two copies of the invariant \(E_6\) tensor \(d^{MNP}\). This is pretty cool and the added single derivative on the right-hand side (relatively to the Yang-Mills gauge transformations' commutator which has no derivatives) makes the commutator somewhat supersymmetry-like (but all these objects are bosonic; nevertheless, this bosonic gauge symmetry seems as powerful as supersymmetry in determining all the couplings in the action).

You should read the paper itself but I just end up this blog post by saying that they explicitly find the two solutions of the constraints above. One of them preserves \(GL(6)\) and interprets the vacuum instantly as 11D SUGRA (M-theory...) on a 6-torus; the other one preserves \(GL(5)\times SL(2)\) and interprets the vacuum as type IIB SUGRA (IIB string) on a five-torus.

If that works and if fermions with SUSY may be added (it surely looks like a worm of can to consider \(256\)-dimensional chiral spinors that are minimal in \(32\) dimensions, it looks like too much but maybe it is exactly OK for SUGRA), this is a new formulation of the maximally supersymmetric supergravity theories that makes the noncompact symmetry group manifest! That's cool but some further progress would probably be needed to define the whole UV-complete string/M-theory (in its maximally supersymmetric vacua) with the manifest U-duality groups. For example, we may ask: Is there a variation of this formalism that defines the so far unknown BFSS-like matrix model for M-theory on \(T^6\)? Or higher?

The explanations of the origin of exceptional symmetries in string/M-theory have been among five top research topics of mine in the recent decade or so. I've actually reached conditions similar to the constraints above but from a very different perspective – from attempts to generalize the Dirac quantization rule and T-duality lattices to the exceptional nonperturbative case. The field-theory limit of my construction is probably described in this very paper and it hasn't been clear to me. I will have to think about it more.

The authors have announced the exceptional field theory in an August 2013 [PRL] paper that I mostly missed and they are preparing the second part of the today's preprint, too.

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reader anna v said...

"So I don't even understand why the sexes of the ultimate parents
couldn't have been reversed. Wouldn't it be more natural to say that
women, who are really free of body hair, inherited this feature from our
ultimate female ancestor, a pig, while men are more hairy after our
forefather chimp? ;-)"

You forgot the hands. When I was in high school it was the existence of the hand that was tooted as all important in the progress from from lower to a chimp to a human. A male chimp could grab a female pig a male pig would have to convince the female chimp somehow :).

On the male female business, of course there are biologically induced differences, which were advantageous for the survival of the species. Somebody has to look after the young, it had to be biologically programmed so, for the survival of all mamals and birds and maybe some other genera. ( that is if you think that the theory of evolution is correct).

It would be interesting to see whether at birth there exists such a definite difference and how much of it is biologically programmed and how much societal.Also it would be interesting to see the size of the effect In societies where the roles of men and women are completely not interchangeable for example, as in in islamic societies, .

reader john said...

The mother is a chimp because of backcrossing. Our genetic material is very close to the genetic material of a chimp, so the hybrid should remain with chimp and reproduce with chimps. Therefore it chimp should be the mother. Otherwise pig would look after after it and it would live with pigs and so on.

reader kashyap vasavada said...

Dear Lubos: A (naive) question: when you say "So to make this group manifest, we clearly need to add 27 compact dimensions (aside from the 4+1 noncompact ones) and not just 6 of them." I thought all theories have to compactify upto 4 dimensions. Where is that extra 1 coming from? Or are they talking about internal symmetries?

reader Luboš Motl said...

Dear Kashyap, I don't follow your question at all. Why should the number of compactified dimensions be bounded by 4? It is surely not. For example, here we are considering SUGRA with 6 compact dimensions. That's the same number of compact dimensions that produces e.g. realistic vacua in perturbative string theory. In M-theory, one has to compactify 7 dimensions (G2 manifolds etc.) to get realistic vacua.

It also makes sense to consider compactifications on 8-dimensional manifolds and with some changes in the qualitative behavior, even more than eight.

reader kashyap vasavada said...

Sorry. I did not put it properly. I thought all theories can have only 4 non compact dimensions , corresponding to our observed universe. If you have 5 non-compact left then you have to still compactify one more. Does this make sense or I am still confusing the issues?

reader Luboš Motl said...

I can't believe this. You have been visiting this blog perhaps for years and you write something like that?

The total number of dimensions - the maximum possible number of uncompactified dimensions - in this Universe is 10 (string theory) or 11 (assuming M-theory). Never heard of that?

reader lucretius said...

I remember watching a long time ago on Japanese television a Japanese scientist (of the kind that study the social behaviour of animals - I think Dawkins used to do that) claiming that our ancestors were ... bears, because apparently we share various aspects of social behaviour with them, and the one that I particularly remembered was not engaging in sexual intercourse in public. But that was a long time ago so I am not sure he would still be able to maintain this view today.

As for these results on the difference between male and female brains: although these scans are claimed to be as something new, their results sound very much like the sort of things my daughter (who basically works on bio-informatics) has been telling me for many years. Therefore I suspect that they have been known (perhaps as a kind of "scientific folklore" ) for a long time and only now people are daring to
speak about them public. Let's hope that this is a sign that change is in the air in other areas which have been blanketed by political correctness.

reader kashyap vasavada said...

Sorry again. This might be a case of misunderstanding the language. Let me understand some more. What I meant was no matter how many dimensions you start with, to bring it down to our universe, eventually we have to be left with only four. But may be that is not what you mean in ST. Perhaps I have to read some more about what you really mean by compact and non compact dimensions. Thanks.

reader Luboš Motl said...

LOL, your argument supports my alternative story where the ultimate mother is female, right? ;-)

I don't get this stuff about convincing. Grabbing the partner still seems like the trivial part of the story to me, our expectations for the female permission notwishstanding; the less nontrivial part of the story is the male upright desire for the contact. ;-)

reader Luboš Motl said...

Oh I see, so your/his model says that the pig is only one of the great great... grandparents and the rest were apes? Why?

If you are saying something else, I am not getting it. I think that mothers and fathers give the same fraction of the genetic material to the offspring and my ancestors lived neither with apes nor with pigs - well, some of them actually lived with (owned) pigs and none of them with monkeys or apes. ;-) At any rate, I am not getting where you seem to get the asymmetry and what is the logic behind it.

reader Luboš Motl said...

M-theory on T^6 is clearly not the vacuum we inhabit. It has the wrong number of large dimensions but it has the wrong spectrum of particles and all other things, too.

String theory doesn't study just the single particular vacuum we inhabit. This paper studies more symmetric, more fundamental, "maximally supersymmetric" vacua. Much of research is focused on such important vacua.

reader kashyap vasavada said...

Thanks. I did not realize they were talking about imaginary world. I kept on comparing with our 4 dim world.

reader Luboš Motl said...

It's not an imaginary world. It's just a different environment than the environment that surrounds us but this other environment is a solution to the same laws of physics.

Most of string theory research is about "different worlds". String phenomenology - analyses of the world that is or may be ours - however important is just a small part of the string theory research.

reader kashyap vasavada said...

Sorry. I see your point finally!!! Thanks.

reader kashyap vasavada said...

Sorry. I did not use the word "imaginary" in any insulting sense. I would like to understand more about ST. Your blog is the only blog which talks about ST in a technical sense. Other blogs use English words only. So in my opinion, capable people like you should keep on pursuing ST. It would be good for physics even if it takes very long time to verify by experiments.

reader john said...

The idea is not mine. He supposes that one pig is involved and the thing born reproduced with an ape, and all the following generations reproduced with apes. This is why our genes are very similar to chimps. Otherwise half of our genes would math with pigs and half of if would match with apes. After some time these pig-apes becomes fertile, that is they can reproduce among themselves. The essential thing is anatomical differences (caused by the pig) does not disappear even if pig-apes only reproduced with apes. I don't know why this is. McCarthy says this is common for hybrid animals. My knowledge comes from , i.e. from the original article. I think you should read it.

reader Vangel said...

"Dear Vangel, do you know of a recipe how to terminate this utterly useless discussion that wastes my time aside from banning you?"

You are free to ban me because it is after all your site. But before you do ban me you might ask yourself what the right answer really is. You seem to think that you can measure something called inflation by using an arbitrary basket of goods and tracking the adjusted price changes. The fact that nobody on this planet experiences the same price changes that are supposedly reflected in that basket of goods seems to be irrelevant. For example, someone like me, who tends to spend a great deal on books has a basket of goods that is very different than the one chosen by the BLS. And being an investor in shares of what I hope are good businesses what happens to the price of the shares that I acquire seems to be important. I imagine that is the same for old people who tend to purchase bonds because they wish to buy income streams. Then there are the massive changes made by producers that obfuscate price changes. Many producers have changed packaging sized so while the price of their box of cereal may be the same you are still getting less than you used to. Others may change the ingredient list and substitute cheaper and lower quality items for those that were removed. There is no way for the data gatherers to catch all this and no way for them to set a proper weighting for each item in their basket because we do not live in a static world.

You my friend are a Keynesian because you reduce the real world economy to aggregates. (If you claim to be a Monetarist please understand that they use even higher order aggregation than Keynes did.) Yet you see yourself as a supporter of free markets and against central planning. The irony is that you defend the central planning activities of the Fed as irrelevant even at a period of time when the Fed owns a third of the government treasuries and is increasing the pace of its intervention in the mortgage markets and elsewhere.

My prediction, which will show which one of us is better informed about how the real economy works, is that we will see a blow off top that will end when the treasury and currency bubbles pop. At that time the Federal Reserve Note will be seen as just another piece of paper that is backed by the debts of a bankrupt government that cannot meet its obligations.
I think at that point we will see debt deflation that coincides with the decline of the currency. In the end the only stability can be brought by backing the new currency by something tangible. You are clearly a very smart guy so why you refuse to do some basic reading on these issues is somewhat puzzling.

reader Vangel said...

"Your denial of the importance - or very existence - of these numbers is analogous to the denial that we can measure any temperatures in meteorology etc. "

I do not deny that you can measure the temperature outside or go to the store and see what the price of a pound of tomatoes is. What I do deny is that you can come up with some general conclusion by aggregating different measurements that are adjusted in an arbitrary manner. In the case of temperature we do not see a material increase in measured temperatures in the US since the 1930s. Yet, the 'adjusted' temperatures show a very large increase. Note that temperature adjustments have tended to be to the high side most of the time even though the UHI and other effects should have caused the adjustments to be the other way.

Exactly is true for the BLS data. Almost all the adjustments are to the low side as any increase is explained away as a quality improvement or ignored due to the substitution effect. Note that there have been reports of adjustments that made the unemployment numbers look great for Obama just before the election. Note that many of the adjustments come from models that are no better than the models that the AGW crowd uses to push its climate fraud.

You of all people should know better and be capable of being objective. You might want to pick up an old dictionary and see what the word inflation meant before the progressives changed the language in the way that they changed the meaning of the world Liberal.

reader lucretius said...

“You are clearly a very smart guy so why you refuse to do some basic reading on these issues is somewhat puzzling.”

Could it not be puzzling because you yourself are not smart enough to understand the points being made and have stuffed you head with dogmas instead of using it for thinking?

reader Vangel said...

That could be true if you guys could explain how the adjusted price changes for an arbitrary basket of goods can be deemed to be a suitable definition of inflation and could explain why the change in the prices for housing, energy, food, health care, stocks or bonds can safely be ignored. Until you can do that it is safe to assume that the problem is on your side of this argument.

reader Giotis said...

Sorry off topic:

Lubos do you understand this conjecture ?

What I know is that in the large N approximation a D3 brane separated from a stack of D3 branes could be modeled by a probe D3 brane in AdS5xS5. Now this picture is the gravity dual of the SYM in the Coulomb branch U(N) x U(1).

What I don't understnad is how the DBI action of the D3 probe in AdS x S5 (which is a world volume action where the U(1) lives) will capture the physics of SYM U(2) in the Coulomb branch and for N=1.

reader Luboš Motl said...

Thanks! I will temporarily trust you that you are interpreting him faithfully because I haven't read his materials in their entirety.

It sounds bizarre for a single pig to get in the process and imprint itself so strongly after so many generations of only-ape mates. It would sound a bit more plausible to me that there was a time when it was fashionable among pigs to date female chimps and they just created many of these bizarre hybrids, also known and looking as the people, and those just continued as people copulating with each other only. ;-)

reader Eugene S said...

Hello Vangel, your claim that

change in the prices for housing, energy, food, health care, stocks or bonds [is being] ignored

Read the relevant Wikipedia article, then ask about what is unclear on Wikipedia's "Reference Desk".

Your comparison with the "urban heat island" effect in measurement of atmospheric temperatures is beside the point. If such an exaggeration exists, it may add 0.1 or 0.2 degrees kelvin to the so-called temperature anomaly. That is less than one-tenth of one percent of the ~ 286 degrees kelvin of global mean temperature.

If inflation as measured by the computer price index were miscalculated by only 0.1 percent, it would be more accurate than even the compilers of the CPI would claim.

reader Luboš Motl said...

It doesn't matter at all that no one is buying exactly the basket that defines the inflation rate. No one has those 2.3 children than the average American has, either. But these statistical quantities are the average over everyone which means that they reflect what the aggregate, whole economy is doing, and this is where the inflation rate is important.

reader Uncle Al said...

"Exceptional groups are sexy and mysterious" Are they uniformly mirror symmetric? If not, test for vacuum geometric chirality toward fermionic matter. If so, explain the pertinence of Ashtekar variables, Barbero-Immirzi parameter, Chern-Simons corrections to Einstein-Hilbert action; Einstein-Cartan-Kibble-Sciama gravitation that does give general relativity in the limiting case.

Physical theory must be held accountable to empirical falsification. Otherwise it is only mathematics - and we know how poorly Euclid fared against cartography, Bolyai, then Thurston.

reader John Archer said...


While we're on this nonsense... :)

"... a male pig would have to convince the female chimp."

The coupling might not have been consensual. In which case it's odds on that it was an islamic pig [BTW one of that last pair of words is redundant — no points for guessing which] in a gang-bang job backed up by his myriad inbred cousins.

On the other hand, the female chimp might simply have fallen out of her tree, landing arse up temporarily stunned. A jaunty pig out on his afternoon snuffle-n-root might have spotted her plight, thought, "Oh, I say! I've never tried one of those before. I wonder what it's like" and leapt straight in. Hands-free! Problem solved! :)

The true Original Sin perhaps?

I must ask the (previous) Archbish of Cant. But maybe not. I can hear his reply now: "In a very real sense, we're all pigs ... "

reader John Archer said...

Surprise formatting! Note to self: watch it with angle brackets.

P.S. For some reason Disqus won't let me edit.

reader Luboš Motl said...

Dear Vangel, you may define your own basket and your inflation rate but it will be less important than the overall inflation rate which is the appropriate weighted average of the personal ones and plays the role for the aggregate questions.

There is nothing Keynesian about aggregate quantities whatsoever. In fact, monetarism is much more centered at the aggregate quantities than Keynesianism. Aggregate quantities are the essence of any macroeconomics - but you apparently deny this whole field, too.

Whether housing or stocks etc. might be included in a new definition of inflation rate is a legitimate question - I was talking with the vice-chairman of the Czech National Bank about this question once during lunch.

But whatever definition you have, there will be some inflation rate that will matter. The relationship between the new inflation rate and the old one will be approximately understandable and their usage will be analogous.

The fact that there can be several definitions doesn't mean that economics may work well with *no* definition of the inflation rate at all.

reader lucretius said...

Who says that they are ignored? There is headline inflation ( ) and there is CPI and then there are various other indices, based on various models. The important thing is that you can compare results based on using different measures and see if they support the same conclusions. If not, there are various ways to refine these indices. This is the usual way science works and as long as nobody has an ulterior motive and is not trying to suppress "inconvenient views", a better understanding will be achieved. This is, of course, the main difference with AGW - the problem is not that some people are trying to measure global warming etc, the problem is that they are suppressing all the evidence that contradicts the conclusions that they made in advance.

People like you, on the other hand, who keep shouting that nothing can be measured are totally useless and contribute nothing but a lot of noise.

reader Luboš Motl said...

Exactly, Lucretius, there are in some sense "too many numbers" on the inflation rate.

Vangel's reason for talking about the choices is that he would like to ban all of them. If there can't be one number, as unique and important as God, no one is allowed to talk about any numbers. Amen. That's his message. Did I get it right, Vangel?

reader lukelea said...

I've heard that human flesh tastes more like pork than beef! Don't know myself.

reader lucretius said...

Completely off topic piece of news but can't find a suitable thread so I hope it can fit and it seems to me interesting:

reader john said...

I agree that it is weird. It is also weird that pigs have 38 chromosomes. But there are examples in the article that this is possible, i.e. animals with different number of chromosomes can have offspr ings. Also ,if it is true, first pig-apes were probably very different from us, probably something like . It is of course possible that some other pig dated another chimp, but this is not necessary as I understood it. One pig is enough.

reader MoptopTheLibertarian said...

I think the convincing is about the lack of hands to force the issue.

reader Gordon said...

It is blindingly obvious that there are differences both structurally and functionally between male and female brains. It just has been politically incorrect and a career-destroyer to actually say so, and still may be because of the folks like those at Harvard that Lubos mentions. The idea that everyone has to be the same and equal (except some who are more equal than others) not only is stupid, but denies reality.

reader Shannon said...

According to another American study, men's nose is 10% bigger than women's, but smaller than the Neandertal. This is due to men's superior muscular mass that needs more oxygen than women, no matter how big or small men are. Their rib cage and lungs are also bigger than women but smaller than Neandetal. According to the study the nose would be an extension of the lungs rather than the skull. So big nose doesn't mean big brain ;-).

reader Shannon said...

Jeez, who told you that ?

reader Curious George said...

I suspect that Darwin formed his Ape hypothesis before his children had been born. All parents know that the Pig hypothesis is a correct one.

reader Luboš Motl said...

Shannon, I have heard the same thing as Luke many times but believe me, I have no experience to empirically verify the testimonies! ;-)

reader lucretius said...

If you need a confirmation by a very reliable expert:

reader Luboš Motl said...

LOL, it's really the only expert I could endorse. But the moral standards may reduce some of his reliability. ;-)

Just reading the Polish-Czech false friends of the Slavist, it's pretty funny, see:

reader lucretius said...

Yes, indeed, and there are more of them than I had known. I must take this with me next time I visit Prague.

Last weekend I had a Russian friend stay in my house (he came here for a conference and we had lots of absurd problems with inviting him since Russians need visas to come here). We discussed the analogous subject involving Polish and Russian. Now I notices something interesting that we talked about. In Polish of course "niedziela" means Sunday and literally the word derives its meaning from "not working". This is natural as catholic Poles should not work on a Sunday.

But in Russian it means the whole week!

Well, I almost jumped to the conclusion that this explains something about Russian attitude to work (as represented in this great novel made into this superb Soviet film

but then I noticed that according to this page in Czech it means both "Sunday" and a week.

Hm, perhaps it simply reflects the well known Czech habit of preferring to sit on the fence.

reader Ann said...

The graphic of the different connection layouts of m/f brains is really cool!

i have read grisly accounts of 18th century seafaring where the salted barrels of meat on the ship sometimes added extra meat from new 'protein sources' and this meat was called 'long pig', maybe because the bones were longer than the normal pork ones.

reader Honza said...

Nonsense. ;-) Here is, how it is with big noses. Quote from Cyrano de Bergerac, Act 1 (Edmond Rostand):

A great nose is the banner of a great man, a generous heart, a towering
spirit, an expansive soul--such as I unmistakably am, and such as you
dare not to dream of being, with your bilious weasel's eyes and no nose
to keep them apart! With your face as lacking in all distinction--as
lacking, I say, in interest, as lacking in pride, in imagination, in
honesty, in lyricism--in a word, as lacking in nose as that other
offensively bland expanse at the opposite end of your cringing
spine--which I now remove from my sight by stringent application of my

reader Luboš Motl said...

Haha, Lucretius, Czechs and Poles are on the same frequency concerning the nonworking (day), "neděle". The word "neděle" used for the whole week is a sort of rural dialect in Czech; the official and also dominant informal Czech word for "week" is "týden".

The Russian "nonworkingday" meaning "the week" may say something about them, indeed. It's the Orthodox-Catholic boundary I was talking about, too. ;-)

The primary Russian word for Sunday is "voskresenie" which is similar (and probably comes from) to the (Czech or another Slavic) word "vzkříšení", the resurrection (was Jesus resurrected on Sunday at all?).

reader Honza said...

As for pig and apes, it is definitely not a new idea. Rather an old one, centuries old. According to Koran the Jews are the descendants of apes and pigs. Now mentioning something like that in the same article with science, that is of course a new low. ;-(

reader Curious George said...

The hands are totally unhelpful: Chimps have four, and pigs none, humans are in between.

reader Shannon said...

Haha, well you need good lungs to talk to some female ;-)

reader Shannon said...


reader john said...

I think it is more like they have angered god and god turned them to monkeys and pigs (el maide, 60). Of course you are welcomed to disprove me.

reader Honza said...

For example look here -
and you can take it from there.
Either way, the idea of pigs monkeys and people being related is there for quit a while.

reader Vangel said...

First of all, the CPI may measure the "changes in the price level of a market basket of consumer goods and services purchased by households" but that basket is not reflective of what the average consumer or any individual consumer actually purchases. The reported CPI usually has food and energy taken out of the picture. It certainly does not include taxes, fees, and charges that the urban consumer is hit with and does not measure fully the cost of health care and housing. As such it has no meaning because it does not reflect what you think it does.

Second, my comparison with the "urban heat island" effect is NOT beside the point. You can go out and measure the effect yourself or look at the literature and see that the difference between rural and urban temperatures can be several degrees Celsius, which is a far bigger number than the claimed warming since the end of the Little Ice Age. And let me note that I do not dispute that we have warmed up since the end of the Little Ice Age. My point was about the American record, which shows that the temperatures measured in the 1930s were not materially different than current temperatures yet the NOAA has managed to add a warming signal that is more than 0.5F to the actual measurements.

My point is that reported trends are based on inadequate models and faulty data gathering techniques. The same is true of the BLS, which has changed its methodology significantly without applying it to the older data sets. Had that happened we would have seen a 1970s that had very little reported inflation.

My preference is to look to reality rather than models. As I look around I notice that the dollar menu items served by Wendy's and McDonald's are now gone and prices have gone up substantially even though they operate in a highly competitive environment where it is difficult to have high margins on any product for very long.

reader Vangel said...

"It doesn't matter at all that no one is buying exactly the basket that defines the inflation rate. No one has those 2.3 children than the average American has, either. "

I do not have to be as good at math to point out that the census picks up all the children and gets the number by making the appropriate calculation. There is no such process for coming up with inflation since only a small fraction of price changes is picked up cleanly and many prices are totally ignored.

There is no economic theory that predicts that when you increase the supply of money and credit you will see price inflation that will be picked up by a particular basket of goods. The simple fact is that the terms inflation and deflation actually meant the increase or decrease in the supply of money and credit an that the increase and decrease did not manifest themselves equally among all goods or services. It is quite possible to have a liquidity injection flow to stocks, real estate, and debt instruments while prices are stable and for productivity increases to hide the massive inflation in the economy. We know this because that is exactly what happened in the second half of the 1920s when the Fed's injections as it attempted to defend the overvalued Pound caused a speculative boom. We saw the same thing in the late 1990s when the Fed's injections made their way into tech stocks or the 2000s when the Fed's money printing created a massive housing bubble that most economists missed at the time.

I suggest that you use your considerable intellectual horsepower to look at reality as it is, and not as the people who missed the previous bubbles are telling you it is.

reader Vangel said...

"Dear Vangel, you may define your own basket and your inflation rate but it will be less important than the overall inflation rate which is the appropriate weighted average of the personal ones and plays the role for the aggregate questions."

But there is no such measurement being gathered because many prices are left totally out of the picture. Let me remind you that the BLS did not include house price increases when it was reporting the CPI during the housing boom. It reduced the contribution of health care costs to a fraction of what it was as a part of the total spending. It ignored the price of investment vehicles, ignores the tax payments that consumers have to make, and many other items that we all have to deal with in our lives. As such it has little meaning.

Note that in the old days there was no debate about what the inflation rate was because when everyone spoke of inflation they meant the change in the supply of money and credit. While there is trouble defining what can be used as money that problem pales in comparison to the current problem of trying to measure price changes.

"There is nothing Keynesian about aggregate quantities whatsoever. In fact, monetarism is much more centered at the aggregate quantities than Keynesianism. Aggregate quantities are the essence of any macroeconomics - but you apparently deny this whole field, too."

I do not deny that the 'field' exists. I deny that aggregates are meaningful. If I wanted to game the GDP number all I would have to do is build a few $10 billion aircraft carriers each quarter and sink them. The data gatherers would say that GDP went up by a certain amount but society would be much poorer because resources were wasted and consumers would have fewer goods to purchase than they would have had the government decided not to build those carriers.

For data to be useful it has to be meaningful and in this case it clearly isn't because the BLS can come up with any number that it wishes. It can drive the unemployment rate lower by assuming that a large number of people who could work were too discouraged to look for work. It can drive GDP higher by underestimating inflation and making the deflator lower than it should be. The simple fact is that the BLS is to the US government what the IPCC is to the UN.

You can choose to spin things any way you wish but that will not change the way things are. Note that I just provided a link to one of the skeptics who kept explaining why the economy was in trouble and why there was a bubble when the majority of financial analysts, financial reporters, and economists were cheering the Fed's bubble blowing activities. Things have not really changed. After the bubble burst the Treasury and Fed prevented a much needed liquidation and the markets are just as screwed up as they were in 2000 and 2007. What do you think happens when the Fed can no longer afford to own 48% of every bond that matures between 10 and 15 years? Or when it is trapped and has to keep monetizing the debt?

reader Vangel said...

"Whether housing or stocks etc. might be included in a new definition of inflation rate is a legitimate question - I was talking with the vice-chairman of the Czech National Bank about this question once during lunch."

As I said, you don't need a "new" definition when the old one is perfectly fine. As Mises Pointed out, "What people today call inflation is not inflation, i.e., the increase in the quantity of money and money substitutes, but the general rise in commodity prices and wage rates which is the inevitable consequence of inflation. This semantic innovation is by no means harmless."

And your pals at the bank are probably aware that inflation policies lead to capital consumption as, the newly created money and credit destroys the effectiveness of accounting standards and falsifies economic calculations. It creates the illusion of real profits where none exist and causes a great deal of harm once the bubbles burst.

reader Shawnhet said...

II'm sure it is *possible* that high inflation regimes can coexist with low uncertainty but it is much more difficult for that to be the case. Here's a simplified example of why this is the case :

Imagine you are an investor living in estimated 0.5% per annum inflation environment. If you are relatively poor at guessing the future inflation rate, you won't be too badly penalized over the short term *by ignoring it completely*(there are plenty of other uncertainties in all investment decisions). In situation B, when the inflation rate is estimated at 10%, you will have to change your prices based on *your best guess of what prices will be when you are selling your product*.

The change between A & B then will be that under B there will be a lot more unskilled predictions of what the inflation rate is going to be than A. This cannot help but increase the uncertainty in the inflation rate under B (as a direct consequence of the fact that the inflation rate in B is of a higher magnitude).

If you don't care for this example, take a look at Germany in 1923 when inflation was running at(on average 5% a day). In this type of scenario, no one would be able to predict the actual *weekly* inflation rate, to anything like the precision of the weekly rate of current day Germany.

Respectfully, this simple example, is, on its own enough to demonstrate that inflation is not guage invariant.

Cheers, :)

reader Luboš Motl said...

No, (3) isn't locality. (3) is the whole local realism because it says that his photons are (objectively) either LHC or RHC at the moment, but this just ain't the case. His photon is in a superposition-type uncertain state and the translation of this claim to a particular outcome may only be revealed by a measurement that is done.

reader Eugene S said...

The people working at NOAA are not idiots, Vangel. They are certainly aware of distortions introduced by the Urban Heat Island effect. There is some discussion over whether they have fully accounted for it, but I doubt your "more than 0.5 degree Fahrenheit added" claim is shared by many.

If you have ~ 2 percent inflation for many years, eventually you can't afford to offer "dollar menu items" any longer. Price increases may be discontinuous for the precise reason that you acknowledge, namely a highly competitive environment that makes vendors fearful of raising prices in sync with their own increases in production costs... until price stability simply cannot be maintained any longer and then you have a "catch-up" effect, like a stretched rubber band snapping back.

reader lucretius said...

This topic and these points have been thoroughly discussed from all possible angles at least since Milton Friedman's 1976 Nobel Prize acceptance lecture "Inflation and Unemployment". Friedman's main point is essentially the same as Lubos's: what counts is not the inflation rate per se but its variability (i.e. uncertainty).

“This analysis explicitly supposes, first, that inflation is steady or at least no more variable at a high rate than at a low - otherwise it is unlikely that inflation will be as fully anticipated at high as at low rates of inflation; second, that the inflation is, or can be, open, with all prices free to adjust to the higher rate, so that relative adjustments are the same with 20 percent inflation as with a zero inflation; third, really a variant of the second point, that there are no obstacles to indexing of contracts.

Ultimately, if inflation rate of 20% per year were to prevail for many decades these requirements could come fairly close to being met, which is why I am inclined to retain the long-long-run vertical Philips curve. But when a country initially moves to higher rates of inflation, these requirements will be systematically departed from. Any such transitional period may well extend over decades.”

I will also take this opportunity to make another comment on Vangel’s posts. Because he is such a numbskull, who like a Jehovah’s witness answers all arguments by quoting the Holy Scriptures and ends each of his monologues by advising others to read it, not even imagining that these others have actually read every single thing he has read and have understood it better than he (which does not mean that that they have unquestioningly accept it - which is, of course, what Vangel means by “understanding” ), I prefer not to respond to him directly.

However, I wanted to add that in certain countries, for example India, do use food and energy in their official inflation index (which is usually said to measure “headline inflation”) because it is generally agreed that in India “food and energy availability is a major problem of masses” while in the West it is not.
On the other hand, energy and food prices everywhere are subject to seasonal variations due to weather and including them in a measure of inflation is likely to be misleading. Nevertheless, people are certainly aware of such factors, they are being measured, and although they may not be included in official measures of core inflation in the West such as the CPI index or the newer PCE index, there are plenty of other indexes that economists use to derive conclusions about the “rater of inflation”. This is so obvious that I feel embarrassed even to write such trivia.

reader Vangel said...

"Who says that they are ignored? There is headline inflation ( ) and there is CPI and then there are various other indices, based on various models."

They are being ignored. The "models" are underweight components like healthcare that show rising prices and do not measure other components that are very important to individuals and families. There is no justification for using owner's equivalent rent instead of house prices. There is no way to justify substitution where items that have gone up are underweighted and those that fell in price are overweighted because that intentionally understates the price changes.

"The important thing is that you can compare results based on using different measures and see if they support the same conclusions."

The data gathering and adjustment makes it easy for analysts to spin any narrative that they want. This is how the AGW proponents can argue that temperatures have gone up significantly when the actual measurements show that they are not materially different than they were in the 1930s. If you add an artificial warming signature I do not believe your claims of catastrophic warming. The same is true of reports of benign inflation when the data ignores taxes, equity and bond markets, adjusts away real estate price changes, and understates costs for things like tuition, insurance, or health care.

I still prefer to look at inflation and deflation as changes in the supply of money and credit. You print a lot of money and create a lot of credit out of thin air and you will see a huge increase in prices somewhere. The fact that the money may flow to bonds or stocks is not much of a concern and neither is the fact that productivity increases offset the liquidity injections in some markets. What worries me is the capital destruction that we see because of the inflation. The artificially low rates cause planners to miscalculate about the availability of resources. They approve projects only to find that their completion will require much higher expenditures and investors take it on the chin. The further you are from the consumer the bigger the error and in the end you find that many projects that should never have been approved need to be written off entirely.

reader Vangel said...

"Did I get it right, Vangel?"

Actually you could not be more wrong. My message is not that there needs to be one number but that numbers that are meaningless should be treated as such. The fact is, and you have yet to dispute it, that you can't measure the Keynesian aggregates in a meaningful way.

You brought up the number of children per household as an example. Well that number is calculated very simply. You take a look at the TOTAL NUMBER OF KIDS and divide it by the number of households. The CPI samples a portion of goods and services in some markets and weighs them in a manner that does not reflect their rightful proportion of the total economy. As one example, health care spending is a bigger part of GDP than it is in the CPI calculation. And other categories, such as bonds and stocks are not captured in the data at all.

reader Shawnhet said...

I don't really think the Friedman quote argues against my point which is that uncertainty is greater when inflation is higher - he explicitly allows that it may take "decades" to adjust to a higher inflation rate - he doesn't make the same qualtification when the adjustment is to lower inflation(and in fact his hypothetical presupposes that the 20% inflation has no uncertainty in it at all).

Frankly, as I mentioned previously, there are plenty of good real world examples of high inflation with high uncertainty (see Weimar for instance) but AFAIK there are not very many good examples of low inflation - with high uncertainty. I view this as a fundamental to the effect of inflation on prices. (high inflation forces speculation which increases uncertainty).


reader Shawnhet said...

Also, I should mention that I just checked what Friedman actually had to say about the inflation vs. uncertainty relationship and he agrees with me but for different reasons. (Google Friedman 1977 inflation uncertainty)

reader lucretius said...

I don't need to Google, I have most of Friedman's famous papers on my desk.

However, I am not sure what you are claiming. Of course Friedman thinks that high inflation is undesirable (and so does Lubos, at least I have never read anything by him that indicated otherwise). Friedman also points out clearly that high inflation will in general be accompanied by high uncertainty, but he attributes this primarily the the fact that rises in inflation have been the result of unanticipated consequences of policies of governments committed to "stable prices". He also mentions the negative effect of rising inflation on "political cohesiveness" of a country. However, he also points out that, if a government was able to maintain a policy of high but stable inflation, most of these negative effects could be avoided. Of course, at the time that Firedman wrote his most famous papers on the subject, the interest was on the relationship between inflation and unemployment and that is what he is mainly addressing:

“An intermediate possibility is that the system will reach stability at a fairly constant though high average rate of inflation. In that case unemployment should also settle down to a fairly constant level, decidedly lower than during the transition. As the preceding discussion emphasises, increasing volatility and increasing government intervention with the price system are the major factors that seem likely to raise unemployment, not high volatility or a high level of intervention.”

reader Shawnhet said...

I am claiming that high inflation tends to be accompanied by high inflation-uncertainty (I don't see how you can get anything else from my posts). In this context, I am not sure what point you are making. Sure it is possible for inflation to stabilize at higher inflation rates, but this is much less likely to happen than at lower inflation rates.

Lubos' argument that inflation is guage invariant requires that the likelihood of high uncertainty be the same (invariant) in both high and low inflation regimes.

Cheers, :)

reader lucretius said...

I take Lubos argument as being essentially theoretical, since he is ignoring the political difficulties involved in achieving a stable high inflation regime. Friedman says this could be achieved only under certain assumptions, which clearly would be difficult to ensure in the real world. (Although, things have changed a lot since the 1970s. )

reader Shawnhet said...

Well, I'm not sure whether his argument is theoretical or not but it relies on the idea that the inflation rate is not related to the inflation uncertainty which does not seem to be valid experientially and I think there are good theoretical reasons to expect that it will not be so in virtually all cases.

Cheers, :)

reader lucretius said...

I agree that it is difficult to find examples of high and stable inflation, but there are some good approximations. I can think of nothing better than Israel in the 1950s and 1960s. The CPI index was through most of these years in high single digits reaching 10% in 1962 (high by present standards though not be historical ones). This was barely felt by the population since practically everything was linked to the index. The growth rate was steady at about 10% per year - three times higher than the average for Western Europe at the time. Unemployment was fairly low at remained at about the same rate. In the 1970s, rising oil prices destroyed this stability and eventually hyperinflation set in (445% in 1984). However, the fact that a stable inflation rate at just under 10% could be kept for 20 years is an example of sorts.

reader Shawnhet said...

Israel is actually an interesting case - Thanks for that. Based on my *very* brief reading on it, I wonder if the stability was artificially imposed by the linkage mechanism. If so, it may be an example where Lubos' invariance might hold. OTOH, it might be that the linkage might simply have fooled people into thinking that the real uncertainty was less that it actually was. Inflation sure came back with a vengeance in the 70s.

reader Justin Glick said...

Thanks Lubos! This is a very tricky thought experiment, where assumptions get snuck in and it is hard to see.

reader Vangel said...

" However, he also points out that, if a government was able to maintain a policy of high but stable inflation, most of these negative effects could be avoided. "

Well, that shows that Friedman was not as good an economist as you guys think that he is.

To understand how badly Friedman misjudged the Fed's activities in the 1970s we need look further than his February 1970, Newsweek commentary, "A New Chairman at the Fed."

Milton, who was an arrogant elitist who had little trouble with the idea that smart people could act as effective central planners, wrote that Arthur Burns, "is the first person ever named Chairman of the Board who has the right qualifications for that post. Prior chairmen have been able, public-spirited men with high standards of integrity and service. But none has had any training or special competence in the problems of the economy as a whole."

Got that? All you need is a high IQ and special training and you too can plan the monetary policies for the United States. Note that Burns was an absolute disaster as chairman as his academic experience was insufficient to deal with real world complexity.

You would have thought that this experience would blunt Miltion's arrogance but that did not happen. In 2006, just as the housing bubble was bursting and setting the stage for the stock market collapse in the coming years Friedman praised Greenspan by writing in the WSJ that, "His performance has indeed been remarkable. There is no other period of comparable length in which the Federal Reserve System has performed so well."

Given the fact that Friedman has been wrong all along the way and that he is far from a free market advocate when it comes to monetary policy why is it that people who support the free markets would pay any attention to him?

reader Vangel said...

"I am claiming that high inflation tends to be accompanied by high inflation-uncertainty .."

That claim has to be correct because artificial price signals always create more uncertainty. Liquidity injections are always the source of business cycle instability.

reader Vangel said...

"Friedman says this could be achieved only under certain assumptions,..."

The problem is that his theory is not achievable in the real world. Central planners cannot control how individuals react to their initiatives and deal with the unintended consequences. Arthur Burns may have been a smart man and Milton's choice for Fed Chairman. But his actions were a disaster because that intellect was insufficient to deal with the reality.

reader Peter F. said...

While I was only aspiring to get a whiffy and surfacy sense of the meat of this post it provided me with a thorough and positive (or optimistic) sense of the meaning of the concept "cross-fertilization". :-)

reader Vangel said...

"I agree that it is difficult to find examples of high and stable inflation, but there are some good approximantions."

Your definition of 'good' is very different than mine. Israel was highly dependent on American aid and without it would have been doomed economically. And let us note that by relying on money printing and foreign aid it created a weak economy that contracted when inflation rates soared to 400% in the 1980s. Recovery came from market reforms that meant the abandonment of the centrally planned economy since the formation of the state.

A better example of stability can be found in the American and British experiences of the 19th century. Strong economies coincided with a sound currency that kept its purchasing power. Deflation that was created by productivity increases was not a problem because it provided cheaper goods for consumers and more profits for producers.

I suggest that there is no equivalent period where countries experienced high inflation and wealth creation through capital formation.

reader Luboš Motl said...

Justin, well, it's mainly the very simplest experiment with entanglement one may do and the character of the entanglement is always the same.

One is allowed to "get snuck" any assumptions but in science, the main criterion is that the ultimate calculable predictions have to agree with the observations.

reader Luboš Motl said...

Discussion on this continues in the DISQUS thread at:

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