On the resolvent condition in the Kreiss Matrix Theorem
Author(s) -
Randall J. LeVeque,
Lloyd N. Trefethen
Publication year - 1984
Publication title -
bit numerical mathematics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 59
eISSN - 1572-9125
pISSN - 0006-3835
DOI - 10.1007/bf01934916
Subject(s) - resolvent , mathematics , matrix (chemical analysis) , lemma (botany) , complex plane , matrix function , mathematical analysis , mathematical proof , pure mathematics , combinatorics , symmetric matrix , eigenvalues and eigenvectors , geometry , physics , materials science , composite material , ecology , poaceae , quantum mechanics , biology
The Kreiss Matrix Theorem asserts the uniform equivalence over allN ×N matrices of power boundedness and a certain resolvent estimate. We show that the ratio of the constants in these two conditions grows linearly withN, and we obtain the optimal proportionality factor up to a factor of 2. Analogous results are also given for the related problem involving matrix exponentialseAt. The proofs make use of a lemma that may be of independent interest, which bounds the arc length of the image of a circle in the complex plane under a rational function.
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