# Betti group

In a broad sense, the same as a homology group; in a narrow sense, the Betti group is the free part of the homology group with as domain of coefficients the group $\mathbf Z$ of integers, if this homology group is finitely generated. Named after E. Betti (1823–1892).

#### References

 [1] H. Seifert, W. Threlfall, "A textbook of topology" , Acad. Press (1980) (Translated from German) [2] P.S. Aleksandrov, "An introduction to homological dimension theory and general combinatorial topology" , Moscow (1975) (In Russian)