English
If G CommutativeShift A holds and adjunction F ⊣ G is given, then the right adjoint G inherits a commutative shift structure, yielding a CommShift on G.
Русский
Если у правой пары сопряжения есть структура CommShift и дано сопряжение F ⊣ G, то правая сторона G наследует структуру CommShift.
LaTeX
$$$[G.CommShift A] \text{ comes from the adjunction } adj$ via the construction $LeftAdjointCommShift$ and unit/counit maps.$$
Lean4
theorem commShift_of_rightAdjoint [G.CommShift A] :
letI := adj.leftAdjointCommShift A
adj.CommShift A :=
by
letI := adj.leftAdjointCommShift A
refine CommShift.mk' _ _ ⟨fun a ↦ ?_⟩
ext X
dsimp
simpa only [Functor.commShiftIso_id_hom_app, Functor.comp_obj, Functor.id_obj, id_comp,
Functor.commShiftIso_comp_hom_app] using LeftAdjointCommShift.compatibilityUnit_iso adj a X