360 ;;Quote: Kamp extended L with tense operators, 'until' and 'since'; allows definition of any first-order tense

360+ ;;Quote: tense operator 'until'; q1 U q2 iff q2 will be true at some future moment and q1 is true until then

360 ;;Quote: tense operator 'since'; q1 S q2 iff q2 was true at some past moment and q1 has been true since then