Shift compatibility for exact derived pullback coherence #
The localization factors, complex-level unit and compositor, and their localized forms commute with the integer shift. Consequently the unit and compositor of exact derived pullback commute with shift as well.
The compositor proof treats the two parenthesizations of a composite explicitly:
the corresponding CategoryTheory.Functor.CommShift structures are not definitionally the same,
even though the underlying composite functors are. Naturality of the final
pullback's shift isomorphism bridges that distinction before localization
extensionality completes the proof.
The localization comparison for exact derived pullback commutes with shift.
The complex-level identity pullback isomorphism commutes with shift.
The complex-level pullback compositor commutes with shift.
The localized complex-level identity isomorphism commutes with shift.
The localized complex-level pullback compositor commutes with shift.
The unit isomorphism for exact derived pullback commutes with shift.
The compositor isomorphism for exact derived pullback commutes with shift.