existence_overlaps
x existence overlaps y if and only if either (a) the start of x is part of y or (b) the end of x is part of y. Formally: x existence starts and ends during y iff (α(x) >= α(y) & α(x) <= ω(y)) OR (ω(x) <= ω(y) & ω(x) >= α(y))
RO:0002487
relation_between_structure_and_stage
is_a