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https://www.youtube.com/watch?v=OvhyFbsVtmY
Exact Sequence , Direct and Inverse image Sheaves
Harpreet Bedi2012/12/17 に公開
We talk about exact sequence of sheaves and Direct and Inverse image of sheaves
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Brian Droncheff4 年前
Thanks again Harpreet. A question around 13:05 or so. you said that f^(-1)(G(u) = .. I am a bit lost as F is a sheaf on X and U subset X, I don't understand how we G is being re-used on X. instead should this be f^(-1)G(v) = .. ?

https://www.youtube.com/watch?v=VmNxWtG8xxQ
Long Exact Sequence of Sheaves
Harpreet Bedi2012/12/18 に公開
Get a Long Exact sequence of sheaves, from the Godement resolution.
Ref: Algebraic Varieites Kempf, Part III notes Burt

https://www.youtube.com/watch?v=3mg425y8Ze0
Loss of Exactness and Resolution of Sheaves
Harpreet Bedi2012/12/18 に公開
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goodwillhart1 年前
I don't understand the first couple of lines of this lecture. You start with a SES of sheaves, but then write a short exact sequence for an open subset U of X. What is the link between these?
If this were true for all open subsets U of X then it would be true for X. Or, if it were true for only the open subset U, I don't see why 0 -> F1(X) -> F2(X) -> F3(X) should be exact.?
MathProofsable5 年前
Thank you for the? videos, they are a great help.
In your example, don't you want to take a punctured disk small enough that it doesn't intersect the set 2pi*iZ. The kernel of the map Om --> Om* is the inverse of the identity map in Om*??

https://www.youtube.com/watch?v=iazzWijM9h4
SES of Flabby Sheaves
Harpreet Bedi2012/12/18 に公開
Short Exact sequence of Flasque/Flabby Sheaves extends to Global Sections
Ref: Algebraic Varieites Kempf, Part III notes Burt

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