English
If r is sized, then size(rotateL(l, x, r)) = size(l) + size(r) + 1.
Русский
Пусть r ограничено по размеру; тогда размер rotateL(l, x, r) равен size(l) + size(r) + 1.
LaTeX
$$\operatorname{Sized}(r) \Rightarrow \operatorname{size}(\mathrm{rotateL}(l, x, r)) = \operatorname{size}(l) + \operatorname{size}(r) + 1$$
Lean4
theorem rotateL_size {l x r} (hm : Sized r) : size (@Ordnode.rotateL α l x r) = size l + size r + 1 :=
by
cases r <;> simp [Ordnode.rotateL]
simp only [hm.1]
split_ifs <;> simp [node3L_size, node4L_size hm.2.1] <;> abel