>A D-brane can be mapped homeomorphically to a D-sphere except for a point at the top
>this open D-Sphere is called a D-Bag
I'm gonna put my D in your mom.
Why? Why not just an open D-cell? I get d for dimension, but why D for dick? Is this some false flag by Michio "Mochizuki" Cuckoo?
>mfw i just solved the abd conjecture and no one can read my d-proof but i don't care
>>8812202
The D in D-brane actually stands for 'diriclet' as in the boundary conditions of a string embedded on the brane.
>>8812138
A D-brane is not a mathematical object, so it can't be mapped to anything.
>>8813062
irrelevant physical technicality, we can just say it's all math and do what we want.
>>8813071
A D-brane is analogous to a particle. It has a worldvolume, like a particles worldline, that is a manifold. It has physical properties like charge, etc. that can be characterized via bundles.
But the D-brane itself is a purely physical object.
>>8813059
Right. That explains that. Are these boundary conditions imposed on the string or on the brane? If we are talking about the conditions of the string, then why does he even bother talking about D-spheres or D-bags (other than the obvious teabag pun)? He could just say that these branes are modeled using open n-cells, where n is the number of dimensions needed. These may seem (and may be) stupid questions, but atleast they are honest.
>>8813111
D-branes are the boundary conditions for open strings. Like a classical string with its ends tied to a wall.
>>8813112
Thanks.
>>8813095
when you work in the context of a description there is no purely physical anything.
I noticed the name Witten appear in the credits for Black Jesus. I didn't know what to make of it then but now I don't like it. I feel like I should stomp his brains out with my foot but I'm not sure.
>>8813562
Physical Objects can be characterized mathematically but are need not themselves be mathematical.
A D-brane can be characterized by bundles, sheaves, etc. But that doesn't mean a D-brane is literally a bundle/sheaf.
>>8813680
it is always possessing a set like structure, and you can always define maps on sets
>>8813797
No, a D-brane is not a set of anything. Even if you consider like a proton to be a "set" of quarks and gluons, the same doesn't apply for branes. Branes are, by definition, fundamental objects in the universe. They are not composed of anything.
Like an elementary particle in non-stringtheory physics.
>>8813803
if it has a world volume then there are points.
>>8813808
The world-volume has a manifold structure, the brane itself does not.
>>8813809
if the brane traces out a world volume in the space time then just take a slice with zero volume and you'll have points which represents the brane at a phase in its movement through the space time.
>>8813817
You are thinking of the brane from a classical perspective. Branes a priori do not need to abide by any classical notions of geometry or to have a definitive location in spacetime.
>>8813848
Classical? it doesn't matter. The process I described can be made to work, mathematically, regardless of physical significance. and Voila---- d-bags.
>>8813855
No, quantum shit doesn't really work like that.
>>8813862
It doesn't matter, because we are exploiting the mathematical structures to have some fun with naming conventions, nothing more.
>>8813871
If D-Branes could be described with that simple of math we wouldn't have to deal with extremely complicated constructions like derived categories and Fukaya categories to properly describe the brane content of a theory.
>>8813907
category theory is gay and a waste of time, all these terrible quagmires algebraists create for themselves could be rectified in an instant if they had an analyst with them to sort these things out.
regardless, what I have described above is not a d-brane per se, but it is of a certain proximity that I can justify (perhaps poorly) calling it a d-brane.
>>8813111
>teabag pun
lol, foreigner detected.
https://en.wiktionary.org/wiki/D-bag
>>8813971
The Fukaya category is a very analytic construction.
>>8813986
its a category.
>>8813993
All categories are not algebraic in nature.
Ex. You can define a category where objects are complex manifolds and morphisms are holomorphic maps. Does that sound algebraic to you?
>>8814049
>All categories are not algebraic in nature.
I mean not all categories are algebraic in nature.
>>8814049
its not the point, category theory is generally considered to be an algebraists implement.
>>8814090
Well the actual category part only important for describing the entire brane content of the theory. The content of the category, i.e. the objects and morphisms, are what describes the D-Branes and how they are realized as boundary conditions for open strings.
>>8814164
Where did you get that screen cap from senpai?
>>8814491
Chapter 5 of https://www.amazon.com/Dirichlet-Branes-Symmetry-Mathematics-Monographs/dp/0821838482/
>>8814500
Ty anon.
>>8813978
Well played, Witten.
>>8813978
*tips fedora*
This man is a genius.
>>8814542
>>8812138
>claimes to be smart
>can't even spell "brain" correctly
Witten confirmed for branelet [sic!]
>>8815087
brainlet
>mfw I come back to my office to find a string theorist trying to steal my funds and relevance
>>8812291
Try as I might, i cannot find any videos of this man speaking.
>>8815203
He transmits his thoughts through memes.