eldorado.tu-dortmund.de/server/api/core/bitstreams/19d14213-116b-46c9-9210-9383e61d2177/content
coordinates of R7 by x1, . . . , x7. Moreover, we define T 7 := R7/Z7 and three maps α, β, γ : T 7 → T 7 by
α((x1, . . . , x7) + Z7) := (x1, x2, x3,−x4,−x5,−x6,−x7) + Z7
β((x1, . . . , x7) + Z7) := (x1,−x2 [...] {(x1, . . . , x7) + Z7 ∈ T 7|x4, x5, x6, x7 ∈ 1 2 Z}
Fix(β) = {(x1, . . . , x7) + Z7 ∈ T 7|x2, x3, x7 ∈ 1 2 Z;x6 ∈ 1
4 + 1
2 Z}
Fix(γ) = {(x1, . . . , x7) + Z7 ∈ T 7|x1, x3 ∈ 1 2 Z;x5, x7 ∈ 1
4 + 1
2 Z} [...] . . . , x7) + Z7) = (x1,−x2,−x3, x4, x5,−x6,−x7) + Z7
αγ((x1, . . . , x7) + Z7) = (−x1, 1 2
+ x2,−x3, x4,−x5, x6,−x7) + Z7
βγ((x1, . . . , x7) + Z7) = (−x1, 1 2 − x2, x3, x4,−x5,−x6, x7) + Z7
αβγ((x1, …
