(*** yminus_sn *)
definition ylminus (x) (n): ynat ≝
- ypred^n x.
+ (ypred^n) x.
interpretation
"left minus (non-negative integers with infinity)"
qed.
(*** yminus_SO2 *)
-lemma ylminus_one_dx (x): ↓x = x - (𝟏).
+lemma ylminus_unit_dx (x): ↓x = x - (𝟏).
// qed.
(*** yminus_Y_inj *)