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Mathlib.Algebra.Homology.Embedding.IsSupported

Support of homological complexes #

Given an embedding e : c.Embedding c' of complex shapes, we say that K : HomologicalComplex C c' is supported (resp. strictly supported) on e if K is exact in degree i' (resp. K.X i' is zero) whenever i' is not of the form e.f i. This defines two typeclasses K.IsSupported e and K.IsStrictlySupported e.

We also define predicates K.IsSupportedOutside e and K.IsStrictlySupportedOutside e when the conditions above are satisfied for those i' that are of the form e.f i. (These two predicates are not made typeclasses because in most practical applications, they are equivalent to K.IsSupported e' or K.IsStrictlySupported e' for a complementary embedding e'.)

If K : HomologicalComplex C c', then K.IsStrictlySupported e holds for an embedding e : c.Embedding c' of complex shapes if K.X i' is zero whenever i' is not of the form e.f i for some i.

Instances

    If K : HomologicalComplex C c', then K.IsStrictlySupported e holds for an embedding e : c.Embedding c' of complex shapes if K is exact at i' whenever i' is not of the form e.f i for some i.

    • exactAt (i' : ι') (hi' : ∀ (i : ι), e.f i i') : K.ExactAt i'
    Instances
      theorem HomologicalComplex.exactAt_of_isSupported {ι : Type u_1} {ι' : Type u_2} {c : ComplexShape ι} {c' : ComplexShape ι'} {C : Type u_3} [CategoryTheory.Category.{u_4, u_3} C] [CategoryTheory.Limits.HasZeroMorphisms C] (K : HomologicalComplex C c') (e : c.Embedding c') [K.IsSupported e] (i' : ι') (hi' : ∀ (i : ι), e.f i i') :
      K.ExactAt i'

      If K : HomologicalComplex C c', then K.IsStrictlySupportedOutside e holds for an embedding e : c.Embedding c' of complex shapes if K.X (e.f i) is zero for all i.

      Instances For

        If K : HomologicalComplex C c', then K.IsSupportedOutside e holds for an embedding e : c.Embedding c' of complex shapes if K is exact at e.f i for all i.

        Instances For