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## Site Tag Cloud

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

• starting something, but nothing here yet. For the moment this is just a home for

• on Hanany-Witten intersection theory

• In Robinson arithmetic, I recorded the simplest nonstandard model (with a single nonstandard element $\infty$).

• Trying a trivial edit to fix the links.

• starting something – not done yet

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

• I just added a few basic links. I’ll add links to papers where monoidal versions of indexed categories and fibrations have shown up.

Joe M

• starting something – not done yet, but need to save

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

• Y=X in this example, edit for clarity

Anonymous

• fixed broken link to Kate’s website

• (Hi, I’m new)

I added some examples relating too simple to be simple to the idea of unbiased definitions. The point is that we often define things to be simple whenever they are not a non-trivial (co)product of two objects, and we can extend this definition to cover the “to simple to be simple case” by removing the word “two”. The trivial object is often the empty (co)product. If we had been using an unbiased definition we would have automatically covered this case from the beginning.

I also noticed that the page about the empty space referred to the naive definition of connectedness as being

“a space is connected if it cannot be partitioned into disjoint nonempty open subsets”

but this misses out the word “two” and so is accidentally giving the sophisticated definition! I’ve now corrected it to make it wrong (as it were).

• I've edited the About page a little. My initial intention was just to update the technical information but I ended up adding a load more, mainly to expand on the "lab book" view. Given that we've discussed this back-and-forth for quite some time, I felt it time someone started actually modifying the page itself. Of course, if you don't like what I've said then change it!

It is a wiki, after all - even if it isn't an encyclopaedia.

• starting a collection of commented references here. This is to be !include-ed in the References-section of related entries. Therefore this entry starts out with a sub-section and contains nothing else.

• am splitting this off from Lie algebra, for ease of cross-linking.

• I gave this work its full name rather than its subtitle, and renamed the page.

• am starting some minimum here. Have been trying to read up on this topic. This will likely become huge towards beginning of next year

• Added to the entry fuzzy dark matter pointer to Lee 17 which appeared today on the preprint server. This is just a concise 2.5 page survey of all the available literature, but as such is very useful. For instance it points out this Nature-article:

• Hsi-Yu Schive, Tzihong Chiueh, Tom Broadhurst, Cosmic structure as the quantum interference of a coherent dark wave, Nature Physics 10, 496–499 (2014) (doi:10.1038/nphys2996)

which presents numerical simulation of the fuzzy dark matter model compared to experimental data.

• created spectral triple, but so far a bit bizarre:

I give an unorthodox category-theoretic VAGUE definition, which I have reason to think is the right one

and then I record an unusual reference on vonNeumann spectral triple (just because at MO somebody asked for this and I don't like to dig out a link just to throw it away after one reference use like a paper napkin )

• I have spelled out the proof (here) of the claim from

• Michel Dubois-Violette, Ivan Todorov, Exceptional quantum geometry and particle physics II (arXiv:1808.08110)

that the stabilizer in the automorphism group $F_4$ of the octonionic Albert algebra “of a 4d Minkowski subspace” happens to be the exact gauge group of the standard model of particle physics.

• The definition and the annotated bibliography are given for Feynman category.

I wonder how useful this could be in related to elucidate the cohomological and motivic quantization via correspondences (Kan extensions in the setup of Feynman categories can help getting the pushforwards, Connes-Kreimer Hopf algebra, Feynman transform (which in some cases gives coefficients in the formal development of the Feynman integal, basically being partition functions, hence connection to graphs).

• brief category:people-entry for hyperlinking references

• Added section on Cluster spaces, which generalize Convergence spaces.

Anonymous

• starting something