Support of a probability distribution ($\mathrm{supp}\mu =\{x:\mu (U)>0\text{ for every open }U\ni x\}$)

For a probability measure on a topological space, its support consists of the points whose every open neighborhood has positive probability. For a continuous effort distribution supported on an interval, every open subinterval of that interval has positive probability.

An effort support is the support of a probability distribution used to randomize effort in a contest. The all-pay indifference equation with random entry determines this support together with its distribution function.