English
The composition of cycles maps respects composition: cyclesMap'(φ1 ≫ φ2) h1 h3 equals cyclesMap'(φ1) h1 h2 composed with cyclesMap'(φ2) h2 h3.
Русский
Составление циклических отображений сохраняет композицию: cyclesMap'(φ1 ≫ φ2) h1 h3 равно cyclesMap'(φ1) h1 h2 затем cyclesMap'(φ2) h2 h3.
LaTeX
$$cyclesMap'(φ1 ≫ φ2) h1 h3 = cyclesMap'(φ1) h1 h2 ≫ cyclesMap'(φ2) h2 h3$$
Lean4
@[reassoc]
theorem cyclesMap'_comp (φ₁ : S₁ ⟶ S₂) (φ₂ : S₂ ⟶ S₃) (h₁ : S₁.LeftHomologyData) (h₂ : S₂.LeftHomologyData)
(h₃ : S₃.LeftHomologyData) : cyclesMap' (φ₁ ≫ φ₂) h₁ h₃ = cyclesMap' φ₁ h₁ h₂ ≫ cyclesMap' φ₂ h₂ h₃ :=
by
let γ₁ := leftHomologyMapData φ₁ h₁ h₂
let γ₂ := leftHomologyMapData φ₂ h₂ h₃
rw [γ₁.cyclesMap'_eq, γ₂.cyclesMap'_eq, (γ₁.comp γ₂).cyclesMap'_eq, LeftHomologyMapData.comp_φK]