These provide the logical and and the logical or operators. Both are cut-off operations, that is: with and, if the left-hand-side is false then the value is known to be false, so the right-hand-side is not evaluated; with or, if the left-hand-side is true then the value is known to be true, so the right-hand-side is not evaluated

For example:

var inRange : Boolean = (x >= 0) and (x <= 100);
var done : Boolean = (timeRemaining <= 0ms) or cancelled;

Because of type inference, these variables don't need to be explicitly declared as Boolean.