A family composed of countably many discrete families.
Sigma-Discrete Family
See also
SigmaThis entry contributed by Margherita Barile
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Cite this as:
Weisstein, Eric W., with contributions by Margherita Barile. "Sigma-Discrete Family." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Sigma-DiscreteFamily.html