The free part of the homology group with a domain of coefficients in the group of integers (if this homology group is finitely generated).
Betti Group
See also
Homology GroupExplore with Wolfram|Alpha
References
Alexandrov, P. S. Combinatorial Topology. New York: Dover, 1998.Hazewinkel, M. (Managing Ed.). Encyclopaedia of Mathematics: An Updated and Annotated Translation of the Soviet "Mathematical Encyclopaedia." Dordrecht, Netherlands: Reidel, p. 380, 1988.Referenced on Wolfram|Alpha
Betti GroupCite this as:
Weisstein, Eric W. "Betti Group." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/BettiGroup.html