Re: [線代] 一題考古題
※ 引述《silentsecret ()》之銘言:
: 若A、B為n*n實矩陣,AB=BA
: 證明A、B有一共同的eigenvector
: 請問大家了!
over C, there exists some k that is an eigenvalue of A
Let V=ker(A-kI)
AB=BA => V is stable under B.
So, as a morphism, we can consider the restriction B|V
Again, there exists an eigenvector (in V) for B|V.
Then we are done.
PS.This implies that if A has n different eigenvalues,then B is diagonalizable.
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◆ From: 76.94.119.209
※ 編輯: Sfly 來自: 76.94.119.209 (02/15 16:32)
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