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Question

Math 6310 • Algebra

Spring 2007 • Question 4

Let \(G\) be a finite group, let \(H\) be a subgroup of \(G\), and let \(\mathbb {C}[G]\) (respectively, \(\mathbb {C}[H]\)) denote the complex group algebra of \(G\) (respectively, \(H\)). Let \(I_H^G\) denote the functor from the category of finite-dimensional \(\mathbb {C}[H]\) modules to the category of finite-dimensional \(\mathbb {C}[G]\) modules which, on the level of objects, is defined by \[ I_H^G(M)=\mathbb {C}[G]\otimes _{\mathbb {C}[H]}M. \] Prove or disprove: \(I_H^G\) is an exact functor.

Raw LaTeX

Let \(G\) be a finite group, let \(H\) be a subgroup of \(G\), and let \(\mathbb{C}[G]\) (respectively,
\(\mathbb{C}[H]\)) denote the complex group algebra of \(G\) (respectively, \(H\)). Let \(I_H^G\)
denote the functor from the category of finite-dimensional \(\mathbb{C}[H]\) modules to the
category of finite-dimensional \(\mathbb{C}[G]\) modules which, on the level of objects, is
defined by
\[
I_H^G(M)=\mathbb{C}[G]\otimes_{\mathbb{C}[H]}M.
\]
Prove or disprove: \(I_H^G\) is an exact functor.