■n次元平行多面体数(その93)
【1】nが偶数の場合の回転行列(u=π/n)
[1,cosu,cos2u,cos3u,・・・,cos(n−1)u]
[0,sinu,sin2u,sin3u,・・・,sin(n−1)u]
[1,cos3u,cos6u,cos9u,・・・,cos3(n−1)u]
[0,sin3u,sin6u,sin9u,・・・,sin3(n−1)u]
[1,cos5u,cos10u,cos15u,・,cos5(n−1)u]
[0,sin5u,sin10u,sin15u,・,sin5(n−1)u]
[・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・]
各行は直交,また,各行の2乗和はn/2であるから,(2/n)^1/2[A]とする.
[1]n=4
[1,cosπ/4,cos2π/4,cos3π/4]
[0,sinπ/4,sin2π/4,sin3π/4]
[1,cos3π/4,cos6π/4,cos9π/4]
[0,sin3π/4,sin6π/4,sin9π/4]
=
[1,1/√2,0,−1/√2]
[0,1/√2,1,1/√2]
[1,−1/√2,0,1/√2]
[0,1/√2,−1,1/√2]
(2/4)^1/2をかけると
[1,1/2,0,−1/2]
[0,1/2,1/√2,1/2]
[1,−1/2,0,1/2]
[0,1/2,−1/√2,1/2]
[2]n=6
[1,cosπ/6,cos2π/6,cos3π/6,cos4π/6,cos5π/6]
[0,sinπ/6,sin2π/6,sin3π/6,sin4π/6,sin5π/6]
[1,cos3π/6,cos6π/6,cos9π/6,cos12π/6,cos15π/6]
[0,sin3π/6,sin6π/6,sin9π/6,sin12π/6,sin15π/6]
[1,cos5π/6,cos10π/6,cos15π/6,cos20π/6,cos25π/6u]
[0,sin5π/6,sin10π/6,sin15π/6,sin20π/6,sin25π/6]
=
[1,√3/2,1/2,0,−1/2,−√3/2]
[0,1/2,√3/2,1,√3/2,1/2]
[1,0,−1,0,1,0]
[0,1,0,−1,0,1]
[1,−√3/2,1/2,1/2,−1/2,√3/2]
[0,√3/2,−√3/2,1,−1/2,1/2]
(2/6)^1/2をかける.
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【2】nが奇数の場合の回転行列(u=2π/n,s=1/√2)
[1,cosu,cos2u,cos3u,・・・,cos(n−1)u]
[0,sinu,sin2u,sin3u,・・・,sin(n−1)u]
[1,cos2u,cos4u,cos6u,・・・,cos2(n−1)u]
[0,sin2u,sin4u,sin6u,・・・,sin2(n−1)u]
[1,cos3u,cos6u,cos9u,・・・,cos3(n−1)u]
[0,sin3u,sin6u,sin9u,・・・,sin3(n−1)u]
[・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・]
[s,s,s,s,・・・・・・・・・・・・・・・,s]
各行は直交,また,各行の2乗和はn/2であるから,(2/n)^1/2[A]とする.
[1]n=5
[1,cos2π/5,cos4π/5,cos6π/5,cos8π/5]
[0,sin2π/5,sin4π/5,sin6π/5,sin8π/5]
[1,cos4π/5,cos8π/5,cos12π/5,cos16π/5]
[0,sin4π/5,sin8π/5,sin12π/5,sin16π/5]
[1/√2,1/√2,1/√2,1/√2,1/√2]
v1=cosπ/5,v2=cos2π/5,−v2=cos3π/5,−v1=cos4π/5
v1=sin4π/5,v2=sin3π/5,v2=sin2π/5,v1=sinπ/5
=
[1,v2,−v1,−v1,v2]
[0,v2,v1,−v1,−v2]
[1,−v1,v2,v2,−v1]
[0,v1,−v2,v2,−v1]
[1/√2,1/√2,1/√2,1/√2,1/√2]
(2/5)^1/2をかける.
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