return and(rexBuilder,
ge(rexBuilder, e0, s1),
ge(rexBuilder, e1, s0));
case CONTAINS:
return and(rexBuilder,
le(rexBuilder, s0, s1),
ge(rexBuilder, e0, e1));
case PERIOD_EQUALS:
return and(rexBuilder,
eq(rexBuilder, s0, s1),
eq(rexBuilder, e0, e1));