Proving Linear Dependence in Complex Matrix Space

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SUMMARY

The discussion centers on proving the linear dependence of the powers of a complex matrix C, specifically C, C², C³, ..., Ck, where k is an integer dependent on the matrix size n. The Cayley-Hamilton theorem is referenced, asserting that every square matrix satisfies its own characteristic polynomial, which implies that for an n by n matrix, there exists a k such that these powers are linearly dependent. The proof requires understanding the implications of matrix dimensions and characteristic polynomials in linear algebra.

PREREQUISITES
  • Understanding of linear algebra concepts, particularly linear dependence and independence.
  • Familiarity with the Cayley-Hamilton theorem and its application to matrices.
  • Knowledge of complex matrices and their properties.
  • Basic understanding of vector spaces and their dimensions.
NEXT STEPS
  • Study the Cayley-Hamilton theorem in detail, focusing on its implications for matrix powers.
  • Learn about the characteristics of complex matrices and their eigenvalues.
  • Explore linear dependence proofs in vector spaces, particularly in the context of matrices.
  • Investigate polynomial equations associated with matrices and how they relate to linear transformations.
USEFUL FOR

Students and professionals in mathematics, particularly those studying linear algebra, matrix theory, and complex analysis, will benefit from this discussion.

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Homework Statement


If C is a n by n matrix with complex coefficient show that there is an integer k >0 that depends only on n such that C, C^2,C^3,...C^k are lin dependent.

The Attempt at a Solution



Its meant to be a full proof but the only idea I vaguely have is that i^4=i. I'm sure this is something standard to prove but I couldn't find it on google, so a link with an explanation would be appreciated.
 
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I can't remember much linear algebra but I would try considering the following. Suppose the dimension of a vector space is 6. Is it possible to extract 7 linearly independent vectors from that vector space?
 
Cayley-Hamilton tells us that C satisfies its own characteristic polynomial.
 

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