x exists during y if and only if: 1) the time point at which x begins to exist is after or equal to the time point at which y begins and 2) the time point at which x ceases to exist is before or equal to the point at which y ends. Formally: x existence starts and ends during y iff α(x) >= α(y) & α(x) <= ω(y) & ω(x) <= ω(y) & ω(x) >= α(y)

Synonyms: exists during