YES(?,POLY) We are left with following problem, upon which TcT provides the certificate YES(?,POLY). Strict Trs: { not(x) -> xor(x, true()) , implies(x, y) -> xor(and(x, y), xor(x, true())) , or(x, y) -> xor(and(x, y), xor(x, y)) , =(x, y) -> xor(x, xor(y, true())) } Obligation: innermost runtime complexity Answer: YES(?,POLY) The input was oriented with the instance of 'Polynomial Path Order' as induced by the safe mapping safe(not) = {}, safe(xor) = {1, 2}, safe(true) = {}, safe(implies) = {}, safe(and) = {1, 2}, safe(or) = {}, safe(=) = {2} and precedence not > or, implies > not, implies > or, = > not, = > implies, = > or . Following symbols are considered recursive: {} The recursion depth is 0. For your convenience, here are the satisfied ordering constraints: not(x;) > xor(; x, true()) implies(x, y;) > xor(; and(; x, y), xor(; x, true())) or(x, y;) > xor(; and(; x, y), xor(; x, y)) =(x; y) > xor(; x, xor(; y, true())) Hurray, we answered YES(?,POLY)