■DE群多面体の面数公式(その842)

 421の頂点間距離が2のとき,半径は2

 R^2=1+1/3+1/6+1/10+1/15+1/21+1/28+a8^2=4

=1+1/3+1/6+1/10+1/15+1/21+2/7+b8^2

 R^2=12/7+2/7+b8^2=12/7+1/28+a8^2=4

 a8^2=(112−48−1)/28=9/4

 b8^2=(28−12−2)/7=2

===================================

 421の基本単体の頂点は,ρについて

P0(0,0,0,0,0,0,0,0)

P1(1,0,0,0,0,0,0,0)

P2(1,1/√3,0,0,0,0,0,0)

P3(1,1/√3,1/√6,0,0,0,0,0)

P4(1,1/√3,1/√6,1/√10,0,0,0,0)

P5(1,1/√3,1/√6,1/√10,1/√15,0,0,0)

P6(1,1/√3,1/√6,1/√10,1/√15,1/√21,0,0)

P7(1,1/√3,1/√6,1/√10,1/√15,1/√21,1/√28,0)

P7(1,1/√3,1/√6,1/√10,1/√15,1/√21,1/√28,√(9/4))

σについて

P0(0,0,0,0,0,0,0,0)

P1(1,0,0,0,0,0,0,0)

P2(1,1/√3,0,0,0,0,0,0)

P3(1,1/√3,1/√6,0,0,0,0,0)

P4(1,1/√3,1/√6,1/√10,0,0,0,0)

P5(1,1/√3,1/√6,1/√10,1/√15,0,0,0)

P6(1,1/√3,1/√6,1/√10,1/√15,1/√21,0,0)

P7(1,1/√3,1/√6,1/√10,1/√15,1/√21,1/√28,√(2/7),0)

P8(1,1/√3,1/√6,1/√10,1/√15,1/√21,√(2/7),√2)

===================================