English
The exterior algebra is endowed with a graded algebra structure by the degrees i, with the degree pieces ∧^i_M closed under the graded multiplication.
Русский
Внешняя алгебра наделяется градуированной структурой по степеням i, а части ∧^i_M замкнуты относительно градуированного умножения.
LaTeX
$$$ExteriorAlgebra R M \text{ is graded by } i \mapsto \wedge^i_R M$, with $(\wedge^i_R M)\cdot(\wedge^j_R M) \subseteq \wedge^{i+j}_R M$$$
Lean4
@[simp]
theorem liftAlternating_one (f : ∀ i, M [⋀^Fin i]→ₗ[R] N) :
liftAlternating (R := R) (M := M) (N := N) f (1 : ExteriorAlgebra R M) = f 0 0 :=
by
dsimp [liftAlternating]
rw [foldl_one]