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Made a stub for admissible rule with a few examples, after seeing the discussion about negation here
I have expanded logical functor by some stuff taken from the Elephant.
In the course of this I have created stubs for cartesian morphism, evaluation map and touched power object.
I have also done some editorial edits to topos (adding subsections and lead-ins)
I started generalized contact geometry since it was in the g+ news.
Created multiplicative disjunction.
I wanted to be able to point to expectation value without the link being broken. So I added a sentence there, but nothing more for the moment.
I gave diffiety more of an Idea-section
microformal morphism a la Theodore Voronov.
Stub for Morse potential.
New stub Weyl functional calculus redirecting also Weyl quantization. I would like to see ref.
but have no access to it (can anybody help?). I also added a sentence at Idea section of functional calculus reflecting that the previous definition there is not fitting functional calculi in the context of quantization, including Weyl’s case. One should do this generality discussion more carefully. the previous definition said that the functional calculus needs to be a homomorphism (from ordinary functions to operator functions). This is true for the functional calculus described in the entry, but not for the wider usage of the phrase like in Weyl functional calculus. Maybe we can resolve this in a better way.
added a minimum of words at commutative operad (the entry remains a stub)
I’ve been entering corrections into the article theory of algebraically closed fields in response to a chat room discussion, but see that the \underbrace command doesn’t work as expected (see the Definition section). What’s the right way to write what is obviously wanted here?
added the case of dgc superalgebras (here) and expanded the list of examples accordingly
created evolutionary derivative (what Olver calls the “Fréchet derivative of tuples of differential functions”) with basic definitions and properties
I created a stub for hydrogen atom, for the moment just so as to record a reference. In the course of this I ended up touching or creating a few related entries, such as proton, neutron, nucleus (physics), element, periodic table of the elements. But all of these remain stubs at the moment.
created rapidity, just enough to serve as a link from the computation of the singular support of the causal propagator
I gave the definition of symbol order its own entry (an estimate on the decay of the principal symbol of a (psedo-)differential operator that enters the assumptions of the propagation of singularities theorem).
Maybe there is a better name for this? The literature refers to it mostly only in formal notation as “q∈Smρ,δ(X)”.
some minimum at bicharacteristic flow
there was no mention of symplectic struture at cotangent bundle. I have added it: here.
I gave the definition of properly supported pseudo-differential operator its own entry.
I noticed that exceptional Lie algebra was still a missing entry. Just in order to make links work, I created a stub for it. No time for more at the moment.
A while back I had started an overview table propagators - table.
Now I see that a nice table in this spirit, but larger with much more information, has been produced by some M. B. Kocic. I have added pointer to this pdf in a few places.
I gave the entry wave front set more of an Idea-section, and I added pointer to Hörmander’s book.
added to advanced and retarded propagator statement and proof of the expression
ΔR(x,y)=(2π)−(p+1)limε→0+∫e−ikμxμkμkμ+m2−ik0ε/2d4kneeded to be able to point to sign function, so I created it
I have given generalized function its own little entry (it used to be just a redirect to distribution) with some expository words on how to think of and read distributions as “generalized functions”.
Someone started a page called Ahmadnagar. The page is blank otherwise. I tried to find more and googled Ahmadnagar and math and found that in the Ahmadnagar district in India there is a village called Math, with a population of 1851. Strange but it seems true. I have left the nLab page for all to see!
Created a short page for quasi-Borel spaces
I’m pretty sure the definition of a super fiber functor should read ’T = sFinVect’ to agree with the notation earlier in the article rather than the notation in DMOS or Deligne’s paper, where sVect is understood to contain only finite-dimensional super vector spaces. I’ve edited the article to reflect this.
needed to be able to point to direction of a vector.
Added the Frechet space structure on spaces of smooth sections of the smooth vector bundle: here
Created the stub germ of a space, mainly to record the (trivial) insight that the category of germs of spaces is a localization of the category of pointed spaces.
Note that this is not yet a good stub, as it is not interlinked very well. I’m not quite sure where to put it in the table at germ.
I’ve been adding a large number of details to the material Sridhar had started at tripos and also to partial combinatory algebra.
stub at right/left fibration of simplicial spaces to record some references.
Created linear hyperdoctrine.
added the definition to Planck length and to Planck mass and in the course of this cross-linked and slightly expanded correspondingly the entries Compton wavelength and Schwarzschild radius .
created a stub for Dirac current, so far mostly just a pointer to details in A first idea of quantum field theory; and cross-linked with baryogenesis, chiral anomaly, conserved current and Noether’s thoerem
I need to be able to point to linear differential equation, and so I created a minimum entry for this.
Notice that at D-module is missing discussion that these model linear differential equations, but I don’t have the leisure now to do anything about this.
I have brought in some standard stuff to Fourier transform in a new section Over Cartesian spaces. (Superceding the previous section “On the real line”.)
just for completeness and for ease of linking, I gave product of distributions with a smooth function its own entry
I have created an entry-for-inclusion
in order to collect notation and terminology for plane (relativistic) waves (as a glorified “related concepts”-section); and so I am including this now into the relevant entries.
In the course of this I created stubs for speed of light, Compton wavelength and dispersion relation redirecting energy-momentum relation, but no substantial content yet in any of these stub entries.
I’ll go next and harmonize Fourier transform with this.
(Previously I had had the ambition there to stick with the convention where the “2π” is in the exponents, instead of in the global prefactors; but I feel now that this is just too different from established practice, and I’ll change it.)
I keep adding basic material to Fourier transform and copying paragraphs over to the respective stand-alone entries, where missing.
Now I added the example of the Fourier transform of the delta-distribution here and copied it over to Dirac distribution – Fourier transform.
gave wavelength a bare minimum of content
needed to be able to point to wave vector, so I created a bare minimum entry
needed to be able to point to plane wave, so I created a bare minimum entry
the entry valuation would deserve more clarification on that issue alluded to under “Sometimes one also…” and where the min-style definition appears the max-style definition should also appear.
The entry should say that at least with some qualification added, then a valued field is a normed field with multiplicative norm. – Or should it be semi-normed?
I could fiddle with it, but I feel I don’t quite get why the terminology here is so non-uniform that I am afraid I am missing something and maybe a more expert person should help.
In Scholze 11, remark 2.3 is a useful comment:
The term valuation is somewhat unfortunate: If Γ=ℝ≥0, then this would usually be called a seminorm, and the term valuation would be used for (a constant multiple of) the map x↦−log|x|. On the other hand, the term higher-rank norm is much less commonly used than the term higher-rank valuation.
gave rapidly decreasing function its own entry, for completeness
I gave Parseval”s theorem a stub entry (in the course of bringing in substance into the entry Fourier transform)
I gave Fourier inversion theorem a stub entry (in the course of bringing in substance into the entry Fourier transform)
Intending to write something on Fourier transforms of products of functions, I realized that “convolution product” used to redirect to group algebra, where only the discrete version of the concept was mentioned, and only hidden in a remark somewhere.
As a first step, I have removed the redirect now and created with convolution product a disambiguation entry that indicates the general idea and mentions some classes of examples.
Could be expanded much further.
since in other entries I keep having the need to directly point to it, I created a brief entry non-singular distribution.
The only proposition there currently is (here) the density of the embedding C∞cp(ℝn)↪𝒟′(ℝn). I should find a canonical citation that also C∞(ℝn)↪ℰ′(ℝn) is dense.
Just a brief definition to satisfy links: meromorphic function.
All our entries which wanted to point to something like dualizing module (such as at Verdier duality) or the more general concept in a closed monoidal category (such as at star-autonomous category) used to point to the entry dualizable object, which however did not really discuss this specific concept of “dualizable object”.
Therefore I have now created dualizing object in a closed category and made these entries point to that, instead.
Mentioned that in homological algebra/stable homotopy theory one usually puts additional finiteness conditions on the would-be dualizing object and added a brief remark on Anderson duality as a fundamental example.
I’m a little mystified as to why Chenchang Zhu is putting up her course Winter 2017-2018 seminar on higher structures (Higher Lie Groupoids) on nLab. There isn’t any linkage to the standard entries. A previous version is almost empty Winter 2016-2017 seminar on higher structures, likewise seminar on Grothendieck-Teichmuller theory. lectures on higher bundle theory has a list of links at least.
I have added to the entries
warning that there is also the respective other author, in the same field.
We had attributions mixed up in at least one case, namely Whitehead theorem used to be listed at George Whitehead instead of at J. H. C. Whitehead. (May fault, probably. I have fixed it now.) Somebody might want to check for further inconsistencies.
Also I made John Whitehead another redirect to J. H. C. Whitehead.
I have added to Saunders MacLane and to classical mechanics pointer to
This made me go and harmonize the formatting at Saunders MacLane – Writings a little.
I note that there is a page on codiscrete groupoid and a page on indiscrete category. As they were they did not link to each other. I have added some links, but perhaps some additional remarks on the terminology would be useful.
I started a page on a recent preprint, categorified Dold-Kan correspondence.
while I was adding more references and pointers to KR-theory I have created a brief stub for real algebraic K-theory, just to record the (still unpublished…?) references