A measure algebra which has many properties associated with the convolution measure algebra of a group, but no algebraic structure is assumed for the underlying space.
Hypergroup
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References
Bloom, W. R.; and Heyer, H. The Harmonic Analysis of Probability Measures on Hypergroups. Berlin: de Gruyter, 1995.Jewett, R. I. "Spaces with an Abstract Convolution of Measures." Adv. Math. 18, 1-101, 1975.Referenced on Wolfram|Alpha
HypergroupCite this as:
Weisstein, Eric W. "Hypergroup." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Hypergroup.html