Presheaves and Sheaves

[@MyGeekAdventures]

Wow, that was remarkably clear - thank you! I've struggled with sheafs and presheafs for a while now, and this really helped bring the abstract notions together.

[@aminsheykh9940]

This was a very good explanation. Thanks for saving me my time.

[@romdotdog]

This helped me finally understand sheafs after struggling with it for a day. Thank you so much!!!!

[@craploadofexamples2844]

This is the best explanation of this concept I’ve ever seen.

[@ghazan555]

wao nice way to explain the concept of sheaf...,

[@fbkintanar]

A nicely intuitive explanation of contravariance of restriction maps in the presheaf functor. When I first met the sheaf conditions, they seemed a bit out of the blue, arbitrary, unmotivated. I'm not coming from analysis, but from model-theoretic and categorical logic.

[@mitchellloren3568]

really good explanation, thanks.

[@Theonemen5]

Really good explanations! Thank you.

[@rajanalexander4949]

Excellent explanation; thank you!

[@ronaldjorgensen6839]

thank you

[@ac-dp3jk]

A great video thank you Sir !

[@subhamjaiswal3677]

1:58 u say 'if something is differentiable on V then it's obviously differentiable on U' I think you meant to say the opposite.

[@albertogarcia4177]

I understand a presheaf F is a contravariant functor from the category of the topological spaces Top to the category of abelian groups Ab. At 7:47 what do you mean with s/U_alpha?. Notice it should be an element of some abelian group.

[@brudy100]

excellent!

[@vinbo2232]

May I ask why the presheaf of bounded functions must be constant, please?

[@InquilineKea]

why are restiction maps "restrictions"?

[@rostislavsvoboda7013]

I can't help myself but all I see at 14:16 is just a circle crossing a line at a specific point but no skyscraper near or far. Can someone explain how to look at it please?

[@hollya.g.86]

the speaker didn't really go into it, but I think from looking it up that it's called skyscraper because it represents a whole group or set at a single point in a space. the circle represented the space here, and the line was the values of the members of the group, and the sheaf contains the whole group at a single site in the space.

[@zavvie809]

at 11:40 we have to limit ourselves to holomorphic/entire functions or something

[@pronaybiswas7524]

Can you recommend some books

[@Sunlessmage]

Hi, under which series does this belong ?

[@HarpreetBedimath]

+Sunlessmage Sheaves and Coho

[@mikhailmikhailov8781]

General nonsense ;)

[@Pygmygerbil88]

@@HarpreetBedimath cohomology? so its a sub set of alberaic topology or group theory?

[@oxide5690]

@@Pygmygerbil88 sheaf cohomology can be used in geometry in general, especially algebraic geometry.