English
There is a distributive law for dite and ite on the right: dite p (fun hp => ite q (a hp) (b hp)) c equals ite q (dite p (a) c) (dite p (b) c).
Русский
Существует распределение между dite и ite справа: dite p (λ hp. ite q (a hp) (b hp)) c = ite q (dite p a c) (dite p b c).
LaTeX
$$$ \text{dite}(p,\ lambda hp.\text{ite}(q,a(hp),b(hp)),c) = \text{ite}(q,\lambda hq.\text{dite}(p,a,c),\lambda hq.\text{dite}(p,b,c)) $$$
Lean4
theorem dite_ite_distrib_right {a : p → α} {b : p → α} {c : ¬p → α} :
dite p (fun hp ↦ ite q (a hp) (b hp)) c = ite q (dite p a c) (dite p b c) :=
dite_dite_distrib_right