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2-category 2-category-theory abelian-categories adjoint algebra algebraic algebraic-geometry algebraic-topology analysis analytic-geometry arithmetic arithmetic-geometry book bundles calculus categorical categories category category-theory chern-weil-theory cohesion cohesive-homotopy-type-theory cohomology colimits combinatorics complex complex-geometry computable-mathematics computer-science constructive cosmology deformation-theory descent diagrams differential differential-cohomology differential-equations differential-geometry digraphs duality elliptic-cohomology enriched fibration foundation foundations functional-analysis functor gauge-theory gebra geometric-quantization geometry graph graphs gravity grothendieck group group-theory harmonic-analysis higher higher-algebra higher-category-theory higher-differential-geometry higher-geometry higher-lie-theory higher-topos-theory homological homological-algebra homotopy homotopy-theory homotopy-type-theory index-theory integration integration-theory internal-categories k-theory lie-theory limits linear linear-algebra locale localization logic mathematics measure measure-theory modal modal-logic model model-category-theory monad monads monoidal monoidal-category-theory morphism motives motivic-cohomology nlab noncommutative noncommutative-geometry number-theory of operads operator operator-algebra order-theory pages pasting philosophy physics pro-object probability probability-theory quantization quantum quantum-field quantum-field-theory quantum-mechanics quantum-physics quantum-theory question representation representation-theory riemannian-geometry scheme schemes set set-theory sheaf simplicial space spin-geometry stable-homotopy-theory stack string string-theory superalgebra supergeometry svg symplectic-geometry synthetic-differential-geometry terminology theory topology topos topos-theory tqft type type-theory universal variational-calculus

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    • brief category:people-entry for hyperlinking references

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

    • Used unicode subscripts for indices of exceptional Lie groups including title and links. When not linked, usual formulas are used. See discussion here. Links will be re-checked after all titles have been changed. (Removed two redirects for “E10” from the top and added one for “E10” at the bottom of the page.)

      diff, v11, current

    • A stub for M-theory. What’s supposed to be so mysterious about it? Is it that people don’t even know what form it would take?

    • the link to the picture in the entry Charles Wells is broken. Does anyone know how to fix it or have an alternative picture?

    • starting something. There is nothing to be seen yet, but I need to save.

      v1, current

    • Created a page of that sort of Grothendieck topology.

      v1, current

    • have recovered the pdf file and upload to the nLab server (now here: pdf)

      diff, v9, current

    • In looking for texts that would address the question “What is computation?” and arrive at an answer vaguely akin to path lifting/transport, I found (and have now added pointer to) this text:

      which gets pretty close, in particular in and around their Figure 1.

      diff, v12, current

    • In locally cartesian closed category, I wrote out an explicit proof that pullback functors f *:C/YC/Xf^\ast \colon C/Y \to C/X between slices preserve exponentials (so that Frobenius reciprocity is satisfied).

    • I added more info on pseudo double categories and double bicategories to double category. I also simplified the picture of a square, which had been bristling with scary unnecessary detail. There's a slight blemish in the left vertical arrow, which I can't see how to fix.
    • For now creating page, more to be added soon.

      v1, current

    • Linked to from https://ncatlab.org/nlab/show/orthogonal+factorization+system and https://ncatlab.org/nlab/show/final+functor

      Todo: add more proofs of this result.

      For some reason the xymatrixes were causing errors so I had to comment them out to submit. Here is an example error:

      An error occurred when running pdflatex on the following diagram. \xymatrix@=5em{e \ar[r]^\gamma \ar[dr]_{\gamma’} & GFc \ar[d]^{Gf} \ & GFc’} The error was: Timed out

      How can I fix this?

      v1, current

    • I added to initial object the theorem characterizing initial objects in terms of cones over the identity functor.

    • brief category:people-entry for hyperlinking references

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

    • starting some minimum, for the moment mainly to record some references

      v1, current

    • starting page on \mathbb{Z}-functors

      Anonymouse

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

    • added to polynomial functor the evident but previously missing remark why it is called a “polynomial”, here.

    • the entry braid group said what a braid is, but forgot to say what the braid group is; I added in a sentence, right at the beginning (and fixed some other minor things).

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

      v1, current

    • am too tired to do it now, but on occasion of an MO discussion:

      remind me to insert at smooth manifold the statement and proof that smooth manifolds are equivalently the locally representable sheaves on CartSp (more precisely: the 𝒢=CartSp\mathcal{G} = CartSp-schemes).

    • Created a stub for the conference.

      v1, current

    • I worked on synthetic differential geometry:

      I rearranged slightly and then expanded the "Idea" section, trying to give a more comprehensive discussion and more links to related entries. Also added more (and briefly commented) references. Much more about references can probably be said, I have only a vague idea of the "prehistory" of the subject, before it became enshrined in the textbooks by Kock, Lavendhomme and Moerdijk-Reyes.

      Also, does anyone have an electronic copy of that famous 1967 lecture by Lawvere on "categorical dynamics"? It would be nice to have an entry on that, as it seems to be a most visionary and influential text. If I understand right it gave birth to topos theory, to synthetic differential geometry and all that just as a spin-off of a more ambitious program to formalize physics. If I am not mistaken, we are currently at a point where finally also that last bit is finding a full implmenetation as a research program.

    • changed “an English mathematician of Egyptian origin” to “a British-Lebanese mathematician”.

      In checking his “origin” on Wikipedia…

      …I see that Wikipedia says that Sir Michael Atiyah has died. Today.

      (!?)

      diff, v6, current

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

      v1, current

    • The name was the incorrect “semi-locally simply topological connected space”

      diff, v8, current

    • a minimum entry, for the moment just so as have a place to record the fact that two smooth functions are smoothly homotopic as soon as they are (continuously) homotopic

      (It sure feels like we must have recorded this somewhere already, but I couldn’t find it…)

      v1, current

    • In the definition, the article states "every object in C is a small object (which follows from 2 and 3)". The bracketed remark doesn't seem quite right to me, since neither 2 nor 3 talk about smallness of objects. Presumably this should better be phrased as in A.1.1 of HTT, "assuming 3, this is equivalent to the assertion that every object in S is small".

      Am I right? I don't (yet) feel confident enough with my category theory to change this single-handedly.