Skip to main content
2 of 4
added 43 characters in body
Ben Webster
  • 44.7k
  • 12
  • 126
  • 260

When does an irreducible representation of GL_n(C) stay irreducible after restriction to a finite subgroup?

Let $V = \mathbb{C}^n$ be the standard representation of $\text{GL}_n(\mathbb{C})$, and let $f(n)$ be the largest value of $k$ such that there exists a finite subgroup $G\subset \text{GL}_n(\mathbb{C})$ with the property that every irreducible subrepresentation $W$ of $V^{\otimes k}$ remains irreducible after restriction to $G$. What's known about the function $f$? In particular, is it unbounded?

For example, I think (but am not sure) that $f(2) = 4$, where the finite subgroup is the binary icosahedral group.

Qiaochu Yuan
  • 118.2k
  • 40
  • 447
  • 741