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Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.
Needed to refer within the circle of pages in algebraic geometry
A notion in algebraic geometry.
I just noticed and noted that Gabriella Böhm wrote a book, on generalizations in Hopf world,
Added a reference to today’s
added pointer to:
Add reference to marked 2-limit.
I created hypermonoid, polishing the comments I made in the hypermonoid thread into an article. The last subsection of the article mentions a general technique for constructing hypermonoids which ought to immediately suggest further examples to a quantum group specialist like Zoran, but I am not such a specialist. I also inserted some shameless self-promotion under References.
Removed the sentence
“If has decidable equality, then the negation of equality is a (in fact the unique) tight apartness on , and any function from to any set (with any tight apartness on ) must be strongly extensional.”
because is not true. Assuming WLPO, Cantor space has decidable equality but the negation of equality is still not the tight apartness relation on Cantor space.
Anonymouse
Created doctrinal adjunction. The page could probably use some examples and/or fleshing out.
created directed homotopy type theory
added a Properties-section to pullback
Where does this concept come from? The page lists no relevant references, nor can I find any search results for “quadrable cospan”. Furthermore, the “Note on terminology” mentions the terminology “carrable”, which means something different as far as I can tell (and certainly in the cited references): namely, a morphism along which all pullbacks are admitted.
Fixed/clarified the notation in the definition of local objects in a model category. Added references.
Also added references to (infinity,1)-categorical hom-space in that context.
added pointer to Sorokin 01
There is a small error in the current proof that the category of endofunctors on a Q-category is a Q-category. I am going to correct it as soon as I find my way through the notation (I used it different on the paper). It now reads
The -unit is the dual of the original counit
and the counit is the dual of the original unit
The wrong thing is that , not and that is why the unit and counit got interchanged; they should not get interchanged, but and should. I am going to sort this out. Thus where is unit goes .
Edit: the correct version is now below.
Change 1: Original page describes the fan theorem as requiring the bar to be decidable, claims that the “classical” fan theorem contradicts Brouwer’s continuity principle. The latter claim is not true; I corrected the error. I have stated the result as two separate theorems: the decidable fan theorem, about decidable bars, and the fan theorem, about bars in general.
Change 2: Slightly more information is provided about the relationship between the Fan Theorem and Bar Induction. Eventually, we should make a page about the latter.
Change 3: the section on equivalents to the fan theorem has been fixed somewhat. The section originally asserted that all of the statements provided were equivalent to the decidable fan theorem; in fact, some are equivalent to the decidable fan theorem and some to the full fan theorem.
Added to BF-theory the reference that right now I am believing is the earliest one:
Gary Horowitz, Exactly soluable diffeomorphism invariant theories Commun. Math. Phys. 125, 417-437 (1989)
But maybe I am wrong. Does anyone have an earlier one? I saw pointers to A. Schwarz articles from the late 70s, but I am not sure if he really considered BF as such.
I added a little bit to maximal ideal (first, a first-order definition good for commutative rings, and second a remark on the notion of scheme, adding to what Urs wrote about closed points).
The second bit is almost a question to myself: I don’t feel I really grok the notion of scheme (why it’s this and not something slightly different that’s the natural definition, the Tao if you like). In particular, it’s where fields – simple objects in the category of commutative rings – make their entrance in the notion of covering by affine opens that I don’t feel I really understand.
Added:
A survey of various notions between unital rings and nonunital rings:
changed higher algebra - contents to algebra - contents in context sidebar
Anonymouse
Trivial edit to start discussion.
What’s happening at the start here? We have both tropical rig and semiring defined. The latter is given with the extension by . Is this just duplication with a mistake?
At semiring having given 4 definitions, it says
The nLab uses the second definition to define a semiring, and the fourth definition to define a rig. The first and third are then called nonunital semirings and nonunital rigs respectively.
Do we really have this as a policy?
Created Moufang loop and some links. It would be good to update the proof that the tangent bundle of a Lie group is trivial to include the case of the tangent bundle of a smooth Moufang loop.
a stub (please expand whoever has the energy), for better disambiguation with loop (topology)
changed higher algebra - contents to algebra - contents in context sidebar
Anonymouse
added missing pointer to commutative monoid in a symmetric monoidal category