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    • bare list of references, to be !include-ed into the References-list of related entries

      v1, current

    • bare list of references to be !include-ed into the References-sections of relevant entries

      v1, current

    • added to Jones polynomial pointers to Edward Witten’s slides for his recent talks at the Clay meeting in Oxford.

      Thanks to Bruce Bartlett for providing them!!

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

      Anonymous

      v1, current

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

      v1, current

    • starting something, to record Prop. 7.6 in

      • Alberto Cattaneo, Paolo Cotta-Ramusino, Riccardo Longoni, Configuration spaces and Vassiliev classes in any dimension, Algebr. Geom. Topol. 2 (2002) 949-1000 (arXiv:math/9910139)

      still need to add details – not done yet

      v1, current

    • a bare collection of references to be !include-ed into the References-sections of related entries

      (not done yet…)

      v1, current

    • added this pointer:

      • William James Harvey, Kleinian groups (a survey), Séminaire Bourbaki : vol. 1976/77, exposés 489-506,Séminaire Bourbaki no. 19 (1978), Talk no. 491, p. 30-45 (numdam:SB_1976-1977__19__30_0)

      diff, v2, current

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

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

    • a bare collection of references to be !include-ed into the References-sections of related entries

      v1, current

    • starting something – not done yet

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

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

      v1, current

    • Trying to write down a(nother) set of typing rules.

      v1, current

    • created in order to record this recent article:

      • Jeffrey A. Harvey, Ramanujan’s influence on string theory, black holes and moonshine (arXiv:1909.11477)

      v1, current

    • Hi all, I added an entry for Leibniz’s identity of indiscernibles.

      I thought it would be nice to include a discussion of the way in which univalence refines the identity of indiscernibles, but I am just beginning to learn about UF and was not sure what to say.

      In Awodey’s 2013 exposition of univalence he states:

      “Rather than viewing it as identifying equivalent objects, and thus collapsing distinct objects, it is more useful to regard it as expanding the notion of identity to that of equivalence. For mathematical purposes, this is the sharpest notion of identity available; the question whether two equivalent mathematical objects are “really” identical in some stronger, non-logical sense, is thus outside of mathematics.”

      Thus we can regard univalence as “loosening” the notion of identity in such a way that it validates Leibniz’s law.

      Certainly, I can just add something like this. However, it seems to me that a philosophical notion of equality that accords with intuition may profitably make a distinction between isomorphic structures when they are not “really” equal ontologically. Awodey is making a stance about “mathematical” rather than “real” identity, as is considered in (some formulations?) of Leibniz’s Law.

      Is it possible to think about the connection to Leibniz’s Law like this:

      Equivalence is akin to and entails a kind of “observational equivalence”/indiscernibility.

      Thus we have the following putative principles:

      • Indiscernibility of Identicals–intuitively true
      • Identity of indiscernibles–controversial
      • Indiscernibility is indiscernible from identity–intuitively true, and maintains some of the intent of identity of indiscernibles

      So can we think of Univalence as a refinement that says “Indiscernibility is indiscernible from identity, so we may as well treat indiscernibles as equal by transporting isomorphisms into identifications.”? Or is this not the way to think about this/do folks in UF have a stronger stance such as “real” equality being absurd?

      Best, Colin

    • I should say – for those watching the logs and wondering – that I started editing the entry global equivariant homotopy theory such as to reflect Charles Rezk’s account in a coherent way.

      But I am not done yet. The entry has now some of the key basics, but is still missing the general statement in its relation to orbispaces. Also some harmonizing of the whole entry may be necessary now, as I moved around some stuff.

      So better don’t look at it yet. I hope to bring it into shape tomorrow or so.

      (In the process I have split off global orbit category now.)

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

      v1, current

    • Started something, but have to dash.

      v1, current

    • To record today’s

      • Marius de Leeuw, Tamás Gombor, Charlotte Kristjansen, Georgios Linardopoulos, Balázs Pozsgay, Spin Chain Overlaps and the Twisted Yangian (arXiv:1912.09338)

      v1, current

    • added pointer to

      • Tudor Dimofte, Perturbative and nonperturbative aspects of complex Chern-Simons Theory, Journal of Physics A: Mathematical and Theoretical, Volume 50, Number 44 (arXiv:1608.02961)

      diff, v4, current

    • And now I’ve started Dehn surgery. Be warned however that there may be inaccuracies, or it may be amateurish.

    • a minimum (from my phone) to satisfy links

      v1, current

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

      Anonymous

      v1, current

    • Fixed codecogs, trying to see if xymatrix works.

      diff, v8, current

    • I have moved a Properties-section to strict n-category, taken from (infinity,n)-category (where it serves as a preliminary), which collects the statements from section 2 of Barwick&Schommer-Pries (see the refereces there).

    • Just to be clear, if at wrapped cycle ϕ *[Σ]\phi_\ast [\Sigma] is a multiple of a cycle cc, would we or wouldn’t we say it wrapped it?

    • I finally learned about the general abstract story behind the notion of orientation in RR-cohomology, for RR an E E_\infty-ring, in terms of trivialization of GL 1(R)GL_1(R)-associated \infty-bundles – from this lecture by Mike Hopkins

      I added some remark about that to orientation in generalized cohomology. Needs more polishing and expansion, but I have to interrupt for the moment.

    • brief category:people-entry for hyperlinking references

      v1, current

    • I thought this should be better developed, and it is. Following the work of Sundholm and Ranta, several people are trying to use dependent type theory to understand natural language. This involves a range of things philosophers care about: anaphora, polysemy, modality, factivity, etc.

      It should be interesting to bring this work into contact with the work here on dependent type theory in mathematics and physics. Already I see an overlap in the analysis of modality via a type of worlds, between us here and them in Resolving Modal Anaphora in Dependent Type Semantics on p. 89.

      So I’ve started a page dependent type theoretic methods in natural language semantics to list references, and later results.

    • I gave the entry super vector space some expositional background and a more detailed (pedantic) definition.

    • Added link to group extension entry at https://ncatlab.org/nlab/show/group+extension

      diff, v7, current

    • added some actual text to the category:people entry Roger Penrose

    • I was looking for a place to record a somewhat more global overview of the notion of locally presentable category, its related notions and its generalizations to higher category theory. But somehow all of the existing entries feel too narrow in focus to accomodate this. So I ended up creating now a new entry titled

      Think of this as accomodating material such as one might present in a seminar talk that is meant to bring people with some basic background up to speed with the relevant notions, without going into the wealth of technical lemmas.

      I only just started. Will continue in a moment after a short break…

    • brief category:people-entry for hyperlinking references

      v1, current

    • starting something. Nothing really there yet. But need to save.

      v1, current