English
In a nontrivial ring, monomials with coefficient 1 are distinct: monomial i with coefficient 1 equals monomial j with coefficient 1 if and only if i = j.
Русский
В не тривиальном кольце мононимиалы с коэффициентом 1 различны: monomial i 1 = monomial j 1 ⇔ i = j.
LaTeX
$$$\operatorname{monomial}(i,1) = \operatorname{monomial}(j,1) \iff i=j.$$$
Lean4
theorem monomial_one_eq_iff [Nontrivial R] {i j : ℕ} : (monomial i 1 : R[X]) = monomial j 1 ↔ i = j :=
by
simp_rw [← ofFinsupp_single, ofFinsupp.injEq]
exact AddMonoidAlgebra.of_injective.eq_iff