Tautological/empty/vacuous predicate; it is true regardless of what and how many arguments are given to it; something is the case; x1 is a thing / is anything; x1 and x2 are in any relation.
Tautological/empty/vacuous predicate; it is true regardless of what and how many arguments are given to it; something is the case; x1 is a thing / is anything; x1 and x2 are in any relation.