n∈NCn:P(A)→Ab
C0Z[−]¯
Z[−]
C0IH0(C•)'
−→ I
n∈NHn(C•) : P(A)→Ab
n > 0F:P(A)op →Ab F⊗
P(A)
Cn= 0 Hom (Cn, A)=0 A:P(A)→
Ab
C•(A)
MP(A)C•(M)
C•(A)
A'H0(C•(A)) C•(A)
B(A, C•(A), A)
A
H∗B(A, C•(A), A)⊗AeM'TorP(A)
∗(hM,I)
H∗HomAe(B(A, C•(A), A), M)'Ext∗
F(A)(I, tM)
A M
VP(A)
B(A, C•(A), C•(V)) →B(A, A, V )→V
V=A V =A⊕i
Hn(C•)
n∈NBn(A, C•(A), C•(−))
F(A)Ci
A⊗Ci1(A)⊗ · · · ⊗ Cir(A)⊗Cj
B∗(A, C•(A), C•(−))
IF(A)
hM
hM⊗
P(A)Bn(A, C•(A), C•(−)) 'hM⊗
P(A)A⊗Cn(A)⊗C0'(A⊗Cn(A)⊗A)⊗
AeM
C0=Z[−]
Q
Q•:Ab →Ch+(Ab)
n∈NQnV7→
Z[Vr]r= 2n
Q0=¯
Z[−]
H0(Q•)'Id
n > 0Qn
n∈NHn(Q•) : Ab →Ab