General truth about elements of a matrix to the n-th power?

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Discussion Overview

The discussion revolves around the properties of matrix powers, specifically focusing on the expression for the elements of a matrix raised to the n-th power in relation to its eigenvalues. The context includes theoretical aspects of linear algebra and matrix diagonalization.

Discussion Character

  • Exploratory, Technical explanation

Main Points Raised

  • One participant asserts that for a diagonalizable matrix P with eigenvalues \lambda_1, \cdots, \lambda_n, the element at the a'th row and b'th column of P^n can be expressed as P^n(a,b) = \sum_{i = 1}^n \alpha_i \lambda_i^n, where \alpha_i is independent of n but dependent on a and b.
  • Another participant agrees with this assertion, indicating that it seems correct.
  • A third participant expresses appreciation for the mathematical expression, describing it as "rather pretty."
  • A subsequent reply echoes this sentiment, affirming the beauty of the expression.

Areas of Agreement / Disagreement

There appears to be general agreement among participants regarding the correctness of the initial claim about the matrix elements, though no formal consensus on the conditions or potential weaknesses of the claim is established.

Contextual Notes

The discussion does not address potential limitations or assumptions related to the diagonalizability of the matrix or the nature of the eigenvalues.

nonequilibrium
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Say we have a matrix P with eigenvalues [itex]\lambda_1, \cdots, \lambda_n[/itex] (possibly some are the same) and P can be diagonalized, then we can always say that the element on the a'th row and b'th column of P^n is equal to [itex]P^n(a,b) = \sum_{i = 1}^n \alpha_i \lambda_i^n[/itex] with [itex]\alpha_i[/itex] independent of n (but dependent on a and b).

Correct? And I don't think the conditions can be weakened?
 
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Seems indeed correct.
 
I find it to be rather pretty :)
 
Indeed, it IS pretty! :biggrin:
 

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