Semigroups over probability distributions, as seen in, for example,

- the convolution semigroup, used in divisible processes (what do you call the semigroup of maximum processes?)
- in the transition semigroup of Markov processes.

## Refs

- Ress91
- Ressel, P. (1991) Semigroups in Probability Theory. In H. Heyer (Ed.), Probability Measures on Groups X (pp. 337–363). Springer US DOI.
- Ress11
- Ressel, P. (2011) A revision of Kimberling’s results — With an application to max-infinite divisibility of some Archimedean copulas.
*Statistics & Probability Letters*, 81(2), 207–211. DOI. - RuSz88
- Ruzsa, I., & Székely, G. J.(1988) Algebraic probability theory. . John Wiley & Sons Inc