Processing math: 100%
Not signed in (Sign In)

Not signed in

Want to take part in these discussions? Sign in if you have an account, or apply for one below

  • Sign in using OpenID

Site Tag Cloud

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 definitions deformation-theory descent diagrams differential differential-cohomology differential-equations differential-geometry digraphs duality elliptic-cohomology enriched fibration finite 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 k-theory lie-theory limits linear linear-algebra locale localization logic mathematics 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

Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to nForum
If you want to take part in these discussions either sign in now (if you have an account), apply for one now (if you don't).
    • added a remark (here) that the expression 1i<jn(xjxi) changes sign under exchange of any pair of variables.

      Also tried to beautify the formatting throught the entry.

      diff, v4, current

    • Started this page. No doubt it could be more elegant.

      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

    • I started an idea section at transgression, but it could probably use some going over by an expert. I hope I didn’t mess things up too badly. I was reading Urs’ note on “integration without integration” on the train ride home and fooled myself into thinking I understood something.

      By the way, this reminded me of a discussion we had a while back

      Integrals: Loops space vs target space

    • 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

    • I wrote a little piece at general covariance on how to formalize the notion in homotopy type theory. Just for completeness, I also ended up writing a little blurb at the beginning about the genera idea of general covariance.

    • creating this minimal entry, just to make the term linkable

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

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

      Anonymous

      v1, current

    • Mentioned the alternative terminology “Zappa–Szép product” and added redirects.

      diff, v5, current

    • The cotangent complex theorem

      Natalie Stewart

      diff, v3, current

    • Adding the actual definition.

      Natalie Stewart

      diff, v5, current

    • I have added to orthogonal factorization system

      1. in the Definition-section three equivalent explicit formulations of the definition;

      2. in the Properties-section the statement of the cancellability property.

      Wanted to add more (and to add the proofs). But have to quit now. Maybe later.

    • added section labels and a table of contents

      Anonymous

      diff, v6, current

    • starting page on antithesis partial orders

      Anonymouse

      v1, current

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

      v1, current

    • starting page on zero-dimensional rings

      Anonymouse

      v1, current

    • brief category:people-entry for hyperlinking references

      v1, current

    • starting page on rings with tight apartness

      Anonymouse

      v1, current

    • tried to polish one-point compactification. I think in the process I actually corrected it, too. Please somebody have a close look.

    • brief category:people-entry for hyperlinking references

      v1, current

    • as mentioned in another thread, I have expanded the Idea-section at polarization in order to highlight the relation to canonical momenta (which I also edited accordingly).

    • there is an old article (Berends-Gastman 75) that computes the 1-loop corrections due to perturbative quantum gravity to the anomalous magnetic moment of the electron and the muon. The result turns out to be independent of the choice of (“re”-)normalization (hence what they call “finite”).

      I have added a remark on this in the (g2)-entry here and also at quantum gravity here.

    • I have been expanding and polishing the entry Heisenberg group.

      This had existed in bad shape for quite a while, but now it’s maybe getting into better shape.

      I tried to spend some sentences on issues which I find are rarely highlighted appropriately in the literature. So there is discussion now of the fact that

      • there are different Lie groups for a given Heisenberg Lie algebra,

      • and the appearance of an “i” in [q,p]=i may be all understood as not picking the simply conncted ones of these;

      I also added remarks on the relation to Poisson brackets, and symplectomorphisms.

      In this context: either I am dreaming, or there is a mistake in the Wikipedia entry Poisson bracket - Lie algebra.

      There it says that the Poisson bracket is the Lie algebra of the group of symplectomorphisms. But instead, it is the Lie algebra of a central extension of the group of Hamiltonian symplectomorphisms.

    • starting page on inequality rings or rings with inequality

      Anonymouse

      v1, current

    • starting page on residually discrete local rings

      Anonymouse

      v1, current

    • working on writing out how the “inversion” morphism of a groupoid object naturally arises from this structure.

      Jonathan Beardsley

      diff, v54, current

    • The entry test category which I wrote some time ago, came into the attention of Georges Maltsiniotis who kindly wrote me an email with a kind praise on nlab and noting that his Astérisque treatise on the topic of Grothendieck’s homotopy theory is available online on his web page and that the Cisinski’s volume is sort of a continuation of his Astérisque 301. Georges also suggested that we should emphasise that a big part of the Pursuing Stacks is devoted to the usage of test categories, so I included it into the bibliography and introductory sentence. I hinted to Georges that when unhappy with a state of an nlab entry he could just feel free to edit directly.

    • Have added to pushout-product the statement (here) that pushout product of I1-cofibrations with I2-cofibrations lands in (I1I2)-cofibrations; and (here) the example of pushout products of the inclusions Sn1Dn. Both without proof for the moment.

    • brief category:people-entry for hyperlinking references

      v1, current

    • Added a paper:

      • Joseph A. Goguen, What is a concept?, (2005). In: Dau, F., Mugnier, ML., Stumme, G. (eds) Conceptual Structures: Common Semantics for Sharing Knowledge. ICCS 2005. Lecture Notes in Computer Science, vol 3596. Springer, Berlin, Heidelberg, (pdf)

      diff, v11, 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

    • I fixed a link to a pdf file that was giving a general page, and not the file!

    • Tried to improve the wording of the first paragraph.

      diff, v7, current

    • the book Monoidal Functors, Species and Hopf Algebras is very good, but still being written. Clearly the current link under which it is found on the web is not going to be the permanent link. So I thought it is a bad idea to link to it directly. Instead I created that page now which we can reference then from nLab entries. When the pdf link changes, we only need to adapt it at that single page.

    • I felt that we had too many gray links to metalanguage, so I gave it a try. But I don’t really have the leisure for it now and not the expertise anyway. Experts please feel invited to take apart what I wrote there and replace with it something better.