English
The Mk construction for cocycles₂ A coincides with the inv of isoCocycles₂ A, after transporting via cochainsIso₂ A. This asserts compatibility of Mk₂ with the second cocycles isomorphism.
Русский
Конструкция Mk2 для кокози₂ A совпадает с инверсией изоморфизма isoCocycles₂ A после переноса через cochainsIso₂ A. Это утверждает совместимость Mk₂ с изоморфизмом кокози₂.
LaTeX
$$$cocyclesMk\left((cochainsIso_{2}(A))^{-1} x\right) = (isoCocycles_{2}(A))^{-1} x \text{ for } x \in cocycles_{2}A$$$
Lean4
/-- The 2-cocycles of the complex of inhomogeneous cochains of `A` are isomorphic to
`cocycles₂ A`, which is a simpler type. -/
def isoCocycles₂ : cocycles A 2 ≅ ModuleCat.of k (cocycles₂ A) :=
cyclesMapIso' (isoShortComplexH2 A) _ (shortComplexH2 A).moduleCatLeftHomologyData