Understanding the proof of Cartier duality
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I'm trying to understand the above proof of Cartier Duality.
The step I don't understand is the following
It says
$$ phipsi(a) = ((phi otimes psi) circ Delta(a) = (phi otimes psi)( a otimes a) $$ for all $f,g$
Why does it implies $Delta(a) = a otimes a$?
It may possible that $operatorname{ker}(phi otimes psi)$ is not trivial for all $phi$ and $psi$.
Here the $Delta$ is the co-multiplication map of the Hopf algebra $A$.
algebraic-geometry commutative-algebra hopf-algebras group-schemes
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I'm trying to understand the above proof of Cartier Duality.
The step I don't understand is the following
It says
$$ phipsi(a) = ((phi otimes psi) circ Delta(a) = (phi otimes psi)( a otimes a) $$ for all $f,g$
Why does it implies $Delta(a) = a otimes a$?
It may possible that $operatorname{ker}(phi otimes psi)$ is not trivial for all $phi$ and $psi$.
Here the $Delta$ is the co-multiplication map of the Hopf algebra $A$.
algebraic-geometry commutative-algebra hopf-algebras group-schemes
Somehow it seems transparent to prove that $G(R) cong Hom(G^{check{}}, mathbb{G}_m)$, and then use the statement for $G^{check{}}$. Atleast that's what they is done in Algebraic Geometry - II Mumford Oda.
– random123
Nov 22 at 7:02
add a comment |
up vote
0
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up vote
0
down vote
favorite
I'm trying to understand the above proof of Cartier Duality.
The step I don't understand is the following
It says
$$ phipsi(a) = ((phi otimes psi) circ Delta(a) = (phi otimes psi)( a otimes a) $$ for all $f,g$
Why does it implies $Delta(a) = a otimes a$?
It may possible that $operatorname{ker}(phi otimes psi)$ is not trivial for all $phi$ and $psi$.
Here the $Delta$ is the co-multiplication map of the Hopf algebra $A$.
algebraic-geometry commutative-algebra hopf-algebras group-schemes
I'm trying to understand the above proof of Cartier Duality.
The step I don't understand is the following
It says
$$ phipsi(a) = ((phi otimes psi) circ Delta(a) = (phi otimes psi)( a otimes a) $$ for all $f,g$
Why does it implies $Delta(a) = a otimes a$?
It may possible that $operatorname{ker}(phi otimes psi)$ is not trivial for all $phi$ and $psi$.
Here the $Delta$ is the co-multiplication map of the Hopf algebra $A$.
algebraic-geometry commutative-algebra hopf-algebras group-schemes
algebraic-geometry commutative-algebra hopf-algebras group-schemes
asked Nov 22 at 4:46
grok
607410
607410
Somehow it seems transparent to prove that $G(R) cong Hom(G^{check{}}, mathbb{G}_m)$, and then use the statement for $G^{check{}}$. Atleast that's what they is done in Algebraic Geometry - II Mumford Oda.
– random123
Nov 22 at 7:02
add a comment |
Somehow it seems transparent to prove that $G(R) cong Hom(G^{check{}}, mathbb{G}_m)$, and then use the statement for $G^{check{}}$. Atleast that's what they is done in Algebraic Geometry - II Mumford Oda.
– random123
Nov 22 at 7:02
Somehow it seems transparent to prove that $G(R) cong Hom(G^{check{}}, mathbb{G}_m)$, and then use the statement for $G^{check{}}$. Atleast that's what they is done in Algebraic Geometry - II Mumford Oda.
– random123
Nov 22 at 7:02
Somehow it seems transparent to prove that $G(R) cong Hom(G^{check{}}, mathbb{G}_m)$, and then use the statement for $G^{check{}}$. Atleast that's what they is done in Algebraic Geometry - II Mumford Oda.
– random123
Nov 22 at 7:02
add a comment |
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Somehow it seems transparent to prove that $G(R) cong Hom(G^{check{}}, mathbb{G}_m)$, and then use the statement for $G^{check{}}$. Atleast that's what they is done in Algebraic Geometry - II Mumford Oda.
– random123
Nov 22 at 7:02