| [ KAIST ] in KIDS 글 쓴 이(By): guest (sdf) <202.31.133.21> 날 짜 (Date): 2003년 5월 9일 금요일 오후 01시 22분 15초 제 목(Title): Re: [Q]이 행렬 이름은? Thanks a lot! it's something like exp(pi/2*j) = j in scalar, in matrix-wise form? J^2 = I j^2 = -1 I call it flip matrix because flip(2,2) := [0 1;1 0]; {a1 a2}*flip(2,2) = {a2, a1}; flip(2,2)*{a1; a2} = {a2; a1}; ... {a1, a2 ,... an}*flip(n,n) = {an, a(n-1), a(n-21), ... a1}; flip(n,n)*{a1; a2; ... an} = {an; a(n-1), a(n-2), ... a1}; well anyway, glad to know there's an offiial name, J imdempotent matrix, for such matrix. -sdf |