English
For each n, the (n+1)-th object of the cocomplex yields an exactness condition at the next degree for the constructed resolution.
Русский
Для каждого n выполняется точность цели на следующем уровне резолюции.
LaTeX
$$theorem ofCocomplex_exactAt_succ (n : ℕ) : (ofCocomplex Z).ExactAt (n + 1)$$
Lean4
theorem ofCocomplex_exactAt_succ (n : ℕ) : (ofCocomplex Z).ExactAt (n + 1) :=
by
rw [HomologicalComplex.exactAt_iff' _ n (n + 1) (n + 1 + 1) (by simp) (by simp)]
dsimp [ofCocomplex, CochainComplex.mk', CochainComplex.mk, HomologicalComplex.sc',
HomologicalComplex.shortComplexFunctor']
simp only [CochainComplex.of_d]
match n with
| 0 => apply exact_f_d ((CochainComplex.mkAux _ _ _ (d (Injective.ι Z)) (d (d (Injective.ι Z))) _ _ 0).f)
| n + 1 => apply exact_f_d ((CochainComplex.mkAux _ _ _ (d (Injective.ι Z)) (d (d (Injective.ι Z))) _ _ (n + 1)).f)