Find the decomposition of the standard two-dimensional rotation

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SUMMARY

The discussion focuses on decomposing the standard two-dimensional rotation representation of the cyclic group Cn into irreducible representations using character theory. The key task involves calculating the character of Cn acting by rotations on the plane and finding its inner product with the irreducible one-dimensional representations. The initial approach of identifying G-invariant subspaces was deemed insufficient, emphasizing the necessity of utilizing characters for the solution.

PREREQUISITES
  • Understanding of cyclic groups, specifically Cn.
  • Familiarity with representation theory and irreducible representations.
  • Knowledge of character theory in the context of group representations.
  • Basic concepts of linear algebra, particularly G-invariant subspaces.
NEXT STEPS
  • Study the character table of the cyclic group Cn.
  • Learn how to compute the inner product of characters in representation theory.
  • Explore the process of decomposing representations into irreducible components.
  • Investigate the relationship between G-invariant subspaces and characters in representation theory.
USEFUL FOR

This discussion is beneficial for students and researchers in mathematics, particularly those studying representation theory, group theory, and linear algebra. It is especially relevant for individuals working on problems involving cyclic groups and their representations.

SNOOTCHIEBOOCHEE
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Homework Statement



Find the decomposition of the standard two-dimensional rotation representation of the cyclic group Cn by rotations into irreducible representations



The Attempt at a Solution



Ok i did this directly, finding complementary 1-dimensional G-invariant subspaces. but our teacher said we specifically need to do this using characters, which i have no clue how to do.
 
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Write down the character of C_n acting by rotations on the plane. Find its inner product with the irreducible 1-d reps.
 

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