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Homological finiteness properties of fibre products. (English) Zbl 1443.20080

Summary: We study the homological finiteness property \(F P_n\) of fibre products. A homological version of the \(n -(n + 1) -(n + 2)\) Conjecture is suggested and solved in some cases. Though the Homological 1-2-3 Conjecture is still open, we prove a homological version of the Virtual Surjection Conjecture in the case of virtual surjection on pairs.

MSC:

20J05 Homological methods in group theory
20E22 Extensions, wreath products, and other compositions of groups
20J06 Cohomology of groups