In probability theory, the sample space of an experiment or random trial is the set of all possible outcomes or results of that experiment. A sample space is usually denoted using set notation, and the possible ordered outcomes are listed as elements in the set. It is common to refer to a sample space by the labels "S", Ω, or "U" (for "universal set").
Notations are something that can be set.
( z1 possible :ARG1 ( z2 set :ARG1 ( z3 thing :ARG1-of ( z4 recognize ) ) ) )