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    • am splitting this off from holographic QCD, since the latter is getting too crowded. Prompted by today’s

      • Mohammad Ahmady, Holographic light-front QCD in B meson phenomenology (arXiv:2001.00266)

      v1, current

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

      v1, current

    • added the pointers to the combinatorial proofs of the fiberwise detection of acyclicity of Kan fibrations, currently discussed on the AlgTop list, to the nLab here.

    • I have added at HomePage in the section Discussion a new sentence with a new link:

      If you do contribute to the nLab, you are strongly encouraged to similarly drop a short note there about what you have done – or maybe just about what you plan to do or even what you would like others to do. See Welcome to the nForum (nlabmeta) for more information.

      I had completly forgotton about that page Welcome to the nForum (nlabmeta). I re-doscivered it only after my recent related comment here.

    • This page has been ‘mucked up’. The table has been destroyed giving just a block of text. I could roll back but thought it better for people to see the mess!

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


      v1, current

    • starting something – not done yet but need to save

      v1, current

    • I added to walking structure a 2-categorical theorem that implies that usually “the underlying X of the walking X is the initial X”. This fact seems like it should be well-known, but I don’t offhand know a reference for it, can anyone give a pointer?

    • starting something – this should be the last of the types if light mesons in the list

      v1, current

    • I made some changes to bivector. While the idea section is correct (and should be strictly adhered to!) but the previous definition is wrong in general! The previous definition is consistent and used in wikipedia but it misses both the direct relation of bivectors, trivectors and general polyvectors to determinants as well as the standard nontrivial usage of bivectors in analytic geometry wher bivectors define equivalence classes of parallelograms and in particular with a point in space given define an affine plane. If we adhere to wikipedia and not to standard treatments in geometry (e.g. M M Postnikov, Analytic geometry) then we miss the nontriviality of the notion of bivector and its meaning which is more precise than that of a general element in the second exterior power.

      Bivector in a vector space VV is not any element in the second exterior power, but a DECOMPOSABLE vector in the second tensor power – in general dimension just such elements in Λ 2V\Lambda^2 V have the intended geometric meaning and define vector 2-subspaces and of course affine 2-subspaces if a point in the 2-subspace is given. It is true that every bivector in 2-d or in 3-d space is decomposable, but in dimension 4 this is already not true. Thus the bivectors form a vector space just in the dimensions up to 33. Similarly, trivectors form a vector space just in the dimensions up to 44. In the context of differential graded algebras, polyvector fields are usually taken as arbitrary elements in the exterior powers of vector fields.

    • this is a bare list of references, to be !include-ed as a subsection in the References-sections of relevant entries

      v1, current

    • 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

    • Created page on Paul Fendley for linking from Fusion Categories

      v1, current

    • starting something. Not done yet but need to save

      v1, current