English
If t and t' are disjoint, then interedges(r,s,t) and interedges(r,s,t') are disjoint.
Русский
Если t и t' не пересекаются, то interedges(r,s,t) и interedges(r,s,t') дисjoint.
LaTeX
$$$ \forall s \forall t,t' : Finset \beta, \; \mathrm{Disjoint}(t,t') \Rightarrow \mathrm{Disjoint}(\mathrm{interedges}(r,s,t), \mathrm{interedges}(r,s,t')) $$$
Lean4
theorem interedges_disjoint_right (s : Finset α) {t t' : Finset β} (ht : Disjoint t t') :
Disjoint (interedges r s t) (interedges r s t') :=
by
rw [Finset.disjoint_left] at ht ⊢
intro _ hx hy
rw [mem_interedges_iff] at hx hy
exact ht hx.2.1 hy.2.1