Questions tagged [kahler-differentials]

7 questions
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Maps between Differential/Kähler Forms in Algebraic Geometry

Let $f: X \to Y$ be a morphism of connected schemes over base field $k$ of characteristic zero. By universal property of Kähler differentials & functoriality there are maps $f^*_j:\Omega_Y^j \to f_*\Omega_X^j$ for each $j \in \Bbb N$ inducing maps…
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Kähler potential for $SU(n)$ coadjoint orbit

The coadjoint orbit of the Lie group $SU(n)$ is given by $\mathcal{O}_{SU(n)} = SU(n)/\mathbb{T}_{n-1} \cong \mathbb{C}\mathbb{P}^{n-1} \ltimes \mathcal{O}_{SU(n-1)}$. It is well known that this orbit $\mathcal{O}$ is a homogeneous Kähler manifold,…
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If $B'=B\otimes_AA'$, then the Kähler differentials satisfy $\Omega_{B/A}\otimes_A A'\cong \Omega_{B'/A'}$

Let $B$ and $A'$ be commutative $A$ algebras, and set $B'=B\otimes_AB'$. I am trying to show that as $B$ modules, the modules of Kähler differentials satisfy: $$\Omega_{B/A}\otimes_AA'\cong \Omega_{B'/A'}$$ Now, via the base change property of…
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Proving universal property in Kähler differentials

I have recently been introduced to Kähler differentials. Our lecturer gave a sketch of the proof of how to construct such object. He said that if $A$ is a $k$-algebra, then we can construct the following free module $$\Omega_A^1:=\bigoplus_{a\in…
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What means “top exterior power of the sheaf of differentials $\Omega^1_{X/Y}$” when the rank of $\Omega^1_{X/Y}$ is globally unbounded?

In Conrad's Grothendieck Duality and Base Change, p. 6, it is said: When $f:X\to Y$ is a smooth map of schemes, then $\omega_{X/Y}$ denotes the top exterior power of the locally free finite rank sheaf $\Omega_{X/Y}^1$ on $X$. My question is: for…
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Sections of the Cotangent Sheaf

I'm struggling to prove that the sections for an affine open set $U$ of the cotangent sheaf $\Omega_X^1$ are isomorphic to the Kähler-differential $\Omega_{\mathcal{O}(X)\vert\mathbb{C}}$. First I want to describe my case and my assumptions. I…
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Book on Commutative algebra.

I just learned a little bit about commutative algebra from A term of Commutative Algebra by Allen B. ALTMAN and Steven L. KLEIMAN it's great and I like the writing style. However the book doesn't have a section on kahler differential. I also tried…