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    • I’ve created a page for the Witt vectors. It seems that even with all that I wrote here (don’t worry I had a set of about 10 blog entries I wrote a few months ago that I just condensed, so I didn’t write this whole thing tonight) there are all sorts of things still missing here. The Witt functor is mention at Lambda-ring and there seems to be connections to the field with one element (?!). I just needed to refer to Witt vectors in the next few pages I want to make, so I decided this had to come first. Dieudonne module will need it and obviously Witt cohomology will need it.

    • killed a spam page, now called spam

    • I felt like starting a table infinitesimal and local - table and included it into the relevant entries. So far it reads as follows:

      first order infinitesimal object infinitesimal formal = arbitrary order infinitesimal local = stalkwise finite
      derivative Taylor series germ function
      tangent vector jet germ of curve curve
      Lie algebra formal group local Lie group Lie group
      Poisson manifold formal deformation quantization local strict deformation quantization strict deformation quantization

      Can be further expanded, clearly.

    • The entry Borel-Weil theorem mentions extensions of the theorem to quantum groups, without however giving a reference. I just got an email asking for these.

      The statement dates from August 19, 2009, due to Zoran.

    • I began adding proofs of Lemma 1-4 to the page transfinite construction of free algebras. The layout of the two array environment has to be fixed; proof of 3-4 to be added.

      Any help/suggestion is extremely appreciated!

    • Someone (anonymous) has created an empty page oon finite dimensional vector spaces.

    • needed to point to restricted product, so I created a bare (and unsophisticated) minimum

    • I mostly wanted to record the correct meaning of this term. Then maybe later I can use this as a reference to fix Wikipedia (^_^). But there's a bit more here too.

      imaginary number

    • Edited biholomorphic function to follow the same format as diffeomorphism. In particular, this means that I qualified biholomorphic function to refer only to maps between complex manifolds. Is there a more general definition of holomorphic functions between complex analytic spaces?

    • the entry p-adic number had (and has) its Definition-section filled with a lengthy recollection of the p-adic integers. I have split into two subsections, such as to make it more clear where the actual definition begins.

    • in non-archimedean analytic geometry there is a standard concept of quasi-net used notably in the definition of Berkovich analytic spaces.

      I have created a minumum entry on this, in the course of creating a bunch of non-archimedean analytic entries. But clearly this needs some comment on terminology. Help is welcome.

    • started real space

      (of course that may eventually want to be disambiguated, but maybe for the moment it’s okay)

    • I worked a bit on bringing the list of structures present in a cohesive (oo,1)-topos into shape, expanding it and filling in details. See the table of contents at cohesive (infinity,1)-topos.

    • Added some more (basic) information on complex conjugation to complex numbers.

    • added to moduli space of curves a paragraph mentioning the result by Harer-Zagier on the orbifold Euler characteristic of g,1 being ζ(12g).

    • I have touched étale groupoid and various entries related to this.

      I have made orbit space redirect to orbit, though eventually it might want to be a separate entry.

      Also I have made foliation theory redirect to folitation, though eventually it might want to be a separate entry.

      I have added Deligne-Mumford stack as a “related concept” to étale groupoid, though eventually what I am after is a complex of entries that discusses approaches to a general notion of étale ∞-groupoids and how these sub-entries fit into a more general story.

      So I’ll be creating a stub étale ∞-groupoid, but I am not sure if I have time and energy to have it be more than a reminder for things to look into later.

    • The relation between slope-(semi-)stability of vector bundles and the general concept of (semi-)stability in the sense of geometric invariant theory seems to be a well-kept secret as far as expositions and lecture notes etc. go. One place where I see a genuine review of this relation is

      • Alfonso Zamora Saiz, On the stability of vector bundles, Master thesis 2009 (pdf)

      I have created an entry

      (with a bunch of variant terms redirecting to it) that is presently just a glorified pointer to the relevant pages in this thesis. Then I have added related comments to the existing entries

    • might anyone have an electronic copy of the English version of Brylinski-Zucker 91 “An overview of recent advances in Hodge theory”?

    • have added to normed field the statement that if the product preserves the norm strictly (by equality, not just by inequality) then one speaks of a “valued field”.

    • I created the page walking structure. I’m open to better names for it. It also probably needs to be linked from a bunch of different places.

    • added to real analytic space the statement and reasoning of Whitneys’s theorem (unformatted for the moment, am in a rush)

    • have added some more references to logarithmic geometry and cross-linked a bit. (but there is still no genuine content)

    • I have deleted a sentence that is not correct. See the last discussion on cellular model category.
      By the way, how do you sign in to nLab. I am signed in to the forum but when I edited it was shown as anonymous coward...
    • I have deleted some sentences that are not correct. See the last discussion on cellular model category.
    • I have deleted some statements that are not correct. It is quite obvious that what I have deleted is wrong, in fact the restatement given a few lines later is the verification of the condition that that map is onto (which is definitely not automatic).
    • started a minimum at analytification, mainly interested for the moment in collecting the references now given there which discuss analytification of algebraic (etc.) stacks

    • I have expanded just a little at KR-theory by giving it an actual Idea-paragraph and adding some more references.

    • I gather (via this nice MO comment) that

      The functor that takes linear algebraic groups G to their -points G() constitutes an equivalence of categories between compact Lie groups and -aniosotropic reductive algebraic groups over all whose connected components have -points.

      For G as in this equivalence, then then complex Lie group G() is the complexification of G().

      I have a gap in my education here and would like to fill it. What’s a good source that discusses this statement a bit more? And which one of Chevalley’s articles is this result originally due?

    • I noticed tha tthe entry separable closure existed but was effectively devoid of content. I have now copy-and-pasted the relevant paragraphs from the entry Galois theory into it.

    • I wrote a bit at heap about the empty heap (and its automorphism group, the empty group, which I put in the headline for maximum shock value).

    • Over on MO (in the comments here) Stefan Wendt kindly reminds me of an old nLab entry I once started on B1-homotopy theory. Have added a reference and hope to be adding more.

    • started Hodge cycle, but my battery is dying right this moment….