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    • Explained how to prove the commutativity of addition in EFA

      diff, v11, current

    • I gave Fourier-Mukai transform a bit of an Idea-section. It overlaps substantially with the Definition section now, but I thought one needs to say the simple basic idea clearly in words first. Also added a few more pointers to literature.

    • Anonymous “helpfully” changed the statement

      A matrix is a list of lists.

      to

      A matrix is a function M:[n]×[m]XM:[n]\times[m]\rightarrow X from the Cartesian product [n]×[m][n]\times[m] to a set XX.

      which I have reverted back.

      diff, v12, current

    • a minimum of an Idea-section, but mainly to record some references

      v1, current

    • I added a clearer “The idea” section for Adams operation, and changed the word “functorial” to “natural” in a number of places, because while various sources do say the Adams operations are functorial, they must really be natural transformations from the functor K:TopAbGpK: Top \to AbGp to itself.

      diff, v10, current

    • a stub entry, for the moment just to make the link work

      v1, current

    • Pointed out that the ring of big Witt vectors is represented by the free lambda-ring on one generator (no coincidence; this follows by easy abstract nonsense).

      diff, v32, current

    • have now spelled out at Tor in simple terms how Tor 1 Ab(A,B)Tor_1^{Ab}(A,B) is a torsion group, so far for the case that AA is finite.

    • added to equalizer statement and proof that a category has equalizers if it has pullbcks and products

    • brief category:people-entry for hyperlinking references

      v1, current

    • Rename the page to reflect the fact that coherence and strictification are distinct, but related, theorems.

      diff, v7, current

    • brief category:people-entry for hyperlinking references

      v1, current

    • I have added

      • Paolo Facchi, Giovanni Gramegna, Arturo Konderak, Entropy of quantum states (arXiv:2104.12611)

      and added publication details to

      • A. P. Balachandran, T. R. Govindarajan, Amilcar R. de Queiroz, A. F. Reyes-Lega, Algebraic approach to entanglement and entropy, Phys. Rev. A 88, 022301 (2013) (arXiv:1301.1300)

      and grouped together more discernibly the references on operator-algebraic entropy

      diff, v50, current

    • added at core the remark that the core is right adjoint to the forgetful functor GrpdCatGrpd \to Cat.

    • felt the desire to have an entry on the general idea (if any) of synthetic mathematics, cross-linking with the relevant examples-entries.

      This has much room for being further expanded, of course.

    • The Idea-section at quasi-Hopf algebra had been confused and wrong. I have removed it and written a new one.

    • added various references, notably on computation of graviton scattering amplitudes.

      diff, v15, current

    • Adding reference

      • Peter Freyd, Algebraic real analysis, Theory and Applications of Categories, Vol. 20, 2008, No. 10, pp 215-306 (tac:20-10)

      Anonymous

      diff, v8, current

    • This is a page for Sridhar Ramesh’s notion of introspective theory. Precise definitions to be added.

      Aaron David Fairbanks

      v1, current

    • starting a category:reference-entry.

      Just a single item so far, but this entry should incrementally grow as more preprints appear (similar to what we have been doing at Handbook of Quantum Gravity and similar entries).

      I know that a soft deadline for submissions of at least one of the sections is this December, so I am guessing this is planned to appear in 2024.

      v1, current

    • Have added pointer to:

      • Adam Caulton: Is a particle an irreducible representation of the Poincaré group? [arXiv:2410.02354]

      (but I haven’t more than skimmed it and don’t mean to endorse it).

      diff, v12, current

    • Added remark on geometric realizations of pairs of adjoint functors

      Roman T

      diff, v17, current

    • some minimum, for the moment just to address the issue raised in another thread, here

      v1, current

    • starting a category:reference-page in which to eventually collect pointers to the contributions to this upcoming book collection

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

    • We may be hearing next week about the internal logic of (,2)(\infty, 2)-toposes. Is there anything to say further on this page beyond what we find out at 2-topos?

      diff, v7, current

    • Started something to record today’s article

      • David Kern, Categorical spectra as pointed (,)(\infty,\mathbb{Z})-categories [arXiv:2410.02578]

      v1, current

    • a bare list of references, to be !include-ed into the References-sections of relevant entries (such as at supergeometry and fermion), for ease of synchronization

      v1, current

    • Mike Stay kindly added the standard QM story to path integral.

      I changed the section titles a bit and added the reference to the Baer-Pfaeffle article on the QM path integral. Probably the best reference there is on this matter.

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

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

    • It didn’t seem we had a page for this, and yet it seems notable enough to warrant one, mainly for cross-linking purposes.

      v1, current

    • I have incorporated Jonas’ comment into the text at pretopos, changing the definition to “a category that is both exact and extensive”, as this is sufficient to imply that it is both regular and coherent.

    • creating an entry with just a bare minimum

      v1, current

    • The pages apartness relation and antisubalgebra disagree about the definition of an antiideal: do we assume ¬(0A)\neg(0\in A) or pA,p#0\forall p\in A, p\# 0? Presumably there is a similar question for antisubgroups, etc. In particular, the general universal-algebraic definition at antisubalgebra would give ¬(0A)\neg (0\in A) as the definition (since 00 is a constant and \bot is a nullary disjunction), contradicting the explicit definition of antiideal later on the same page.

      Does this have something to do with whether #\#-openness is assumed explicitly or not? The page apartness relation claims that, at least for antiideals, openness is automatic as long as the ring operations are strongly extensional. But antisubalgebra assumes openness explicitly, in addition to strong extensionality of the algebraic operations.

      Finally, do we ever really need the apartness to be tight?

    • The statement had been laying dormant here for about a dozen years, without a proof. I’ve finally put some meat on the bones.

      diff, v2, current