English
A second variant of HasSubst.monomial' asserting the monomial substitution when exponent is nonzero.
Русский
Второй вариант HasSubst.monomial' утверждает подстановку монома при ненулевом показателе.
LaTeX
$$$ \text{monomial}'(n, s) \text{ holds for } n \neq 0. $$$
Lean4
/-- A choice of gcd of two elements in a Bézout domain.
Note that the choice is usually not unique. -/
noncomputable def gcd : R :=
Submodule.IsPrincipal.generator (Ideal.span { x, y })