English
If x and y are in the support of g, then x and y are in the same cycle of g iff the cycle_of x equals cycle_of y.
Русский
Если x и y лежат в поддержке g, то x и y принадлежат одному и тому же циклу g тогда и только тогда, когда cycleOf x = cycleOf y.
LaTeX
$$$x \\\\in g\\\\.support \\\\land y \\\\in g\\\\.support \\\\Rightarrow (g.SameCycle x y) \\\\iff g\\\\.cycleOf x = g\\\\.cycleOf y$$$
Lean4
theorem sameCycle_iff_cycleOf_eq_of_mem_support [DecidableEq α] [Fintype α] {g : Perm α} {x y : α} (hx : x ∈ g.support)
(hy : y ∈ g.support) : g.SameCycle x y ↔ g.cycleOf x = g.cycleOf y :=
by
refine ⟨SameCycle.cycleOf_eq, fun h ↦ ?_⟩
rw [← mem_support_cycleOf_iff' (mem_support.mp hx), h, mem_support_cycleOf_iff' (mem_support.mp hy)]