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    • Page created, but author did not leave any comments.

      v1, current

    • Page created, but author did not leave any comments.

      Anonymous

      v1, current

    • am starting something. Just saving for the moment, not done yet

      v1, current

    • I added a Definition-section to AKSZ sigma-model with a bit of expanded discussion

    • Getting my contact info in for the communal initiality theorem project.

      Dave Ripley

      v1, current

    • The mathematician who is the subject of this page is known as C. S. Seshadri, and not C. Seshadri as the current title of the page indicates. Correcting it.

      N. Raghavendra

      diff, v2, current

    • Page created, but author did not leave any comments.

      v1, current

    • Page created, but author did not leave any comments.

      v1, current

    • Late last night I was reading in Science of Logic vol 1, “The objective logic”.

      I see that the idea of cohesion is pretty explicit there, not in the first section of the first book (Determinateness, which has the discussion of “being and becoming” that Lawvere is alluding to in the Como preface) but in the second section of the first book, “The magnitude”.

      There the discussion is all about how the continuous is made up from discrete points with “repulsion” to prevent them from collapsing to a single and with “attraction” that keeps them together nevertheless.

      This “attraction” is clearly just the same idea as “cohesion”. One can play this a bit further and match Hegel’s Raunen to formal expressions involving the flat modality and the shape modality pretty well. I made some quick notes in the above entry.

      On the other hand, that section 1 about being and becoming seems to be more about the underlying type system itself. Notably about the empty type and the unit type, I think

    • The definition of braided monoidal category was wrong or at least nonstandard, because it left out one of the hexagon axioms and included a 'compatibility with the unit object' law which follows from the usual definition.

      I changed it to the usual definition.

      If the nonstandard definition is equivalent to the usual one, I'd love to know why! But I don't see how you get two hexagons from one, even given compatibility with the unit object.

      (Of course for a symmetric monoidal category we just need one hexagon.)

      I also beefed up the definition at symmetric monoidal category so the poor reader doesn't need to run back to braided monoidal, then monoidal.
    • Added some remarks, mostly about extensivity and exactness, to quasitopos.

    • Now there is Sylow p-subgroup.


      Is there a compilation, somewhere, of the results “the (obvious) automorphisms of a small 𝔄\mathfrak{A} AA are transitive on AA’s maximal 𝔅\mathfrak{B}s?” The only other example ready in my head is that the maximal tori in a compact Lie group are conjugate, but I know I’ve seen more.

    • maded explicit the identification of equivariant stable homotopy groups with equivariant generalized cohomology groups of the point: here

      diff, v12, current

    • Fixed a typo, but also I noted the last but one link is dead. Does any one know if this has moved somewhere?

      (Edit: I found it. There is a link from his home page. I have updated the link.)

      diff, v7, current

    • I am giving this generalized homology theory its own little entry, so that it becomes possible to refer to it more specifically, beyond broadly pointing to just “stable homotopy groups”.

      (Curious that things are set up such that the most fundamental of homology theories is almost un-nameable, since its canonical name clashes with the name of the whole subject. Curious circularity there.

      The other day I was visiting the Grand Mosque. It’s qibla wall has a huge mosaique displaying the 99 names of God in 99 flowers, plus one flower with no name it in, to represent the un-nameable (one can see it well here, only that the sheer size of it is not brought across by photographs). )

      v1, current

    • Page created, but author did not leave any comments.

      v1, current

    • trivia:

      how to typeset here LaTeX’s \not\subset? Instiki has \nsubset, but on the nLab it comes out with a strangely vertical bar, instead of the usual slanted slash (?) while here on the nForum it comes out completely weird

      ⊂⃒ \nsubset

      diff, v12, current

    • renamed from “geometric fixed points” to “geometric fixed point spectrum”, which is clearly the better/right entry title

      diff, v3, current

    • Added a link to example showing that sober + T_1 does not imply Hausdorff.

      diff, v47, current

    • Page created, but author did not leave any comments.

      Anonymous

      v1, current

    • Missing page, just a definition

      v1, current

    • made sub-sections for the different definitions; slightly expanded the definition in terms of differential forms (here)

      diff, v14, current

    • have re-touched the formatting of this ancient entry from the early days of the nnLab, and added hyperlinks and cross-links

      diff, v5, current

    • minimum on the multicategory of permutative categories, for the moment just as to record references and make hyperlinks work

      v1, current

    • Included some links to his theses and a start on his papers.

      diff, v3, current

    • added a tad more text, to make this a tad more useful to a reader not already familiar with it. But it’s still a stub

      diff, v3, current

    • discovered this ancient entry (while searching for occurences of “permutation matrix” on the nLab). This was in very bad shape, with a ill-rendering floating toc and big query box right at the beginning, then a little bit of content, and then some speculation by a contributor who we had to persuade to leave, long ago.

      I did a minimum of cleaning up, in particular removed the query box, since it had been dealt with. This is what it had said:


      +– {.query}

      Zoran: there are several things called “Birkhoff’s theorem” in various field of mathematics and mathematical physics, and belong even to at least 2 different classical Birkhoff’s. Even wikipedia has pages for more than one such theorem. To me the first which comes to mind is Birkhoff’s factorization theorem, now also popular in Kreimer-Connes-Marcolli work and in connection to loop groups (cf. book by Segal nad Pressley). I would like that the nnlab does not mislead by distinguishing one of the several famous Bikhoff labels without mentioning and directing to 2-3 others.

      Ian Durham: Good point. I think this probably ought to be renamed the “Birkhoff-von Neumann theorem.” Is that a good enough label or should we get more specific with it?

      Toby: I have moved it. See also the new page Birkhoff’s theorem, which is basically just Zoran's comment above. =–


      diff, v9, current

    • stub entry, for the moment just so as to make cross-links work

      v1, current

    • Page created, but author did not leave any comments.

      v1, current

    • stub entry, for the moment just so as to record the reference: the analog of Atiyah-Segal completion, but now for algebraic K-theory over a finite field.

      v1, current

    • Added more publications and preprints to Steve Lack’s page

      diff, v5, current

    • Page created, but author did not leave any comments.

      v1, current

    • added the crucial pointer to

      • Gunnar Carlsson, Equivariant Stable Homotopy and Segal’s Burnside Ring Conjecture, Annals of Mathematics Second Series, Vol. 120, No. 2 (Sep., 1984), pp. 189-224 (jstor:2006940, pdf)

      and a bit more

      diff, v3, current