English
If x ≠ ⊥ in WithBot α, then for all y, y ≤ y + x holds in WithBot α when α is Add, LE, and CanonicallyOrderedAdd.
Русский
Если x ≠ ⊥ в WithBot α, тогда для любого y выполняется y ≤ y + x в WithBot α при Add, LE и CanonicallyOrderedAdd.
LaTeX
$$$\\forall x \\ne \\bot,\\ \\forall y \\in \\mathrm{WithBot}(\\alpha):\\ y \\le y + x$$$
Lean4
protected theorem le_self_add [Add α] [LE α] [CanonicallyOrderedAdd α] {x : WithBot α} (hx : x ≠ ⊥) (y : WithBot α) :
y ≤ y + x := by
induction x
· simp at hx
induction y
· simp
· rw [← WithBot.coe_add, WithBot.coe_le_coe]
exact le_self_add