YES We show the termination of the TRS R: implies(not(x),y) -> or(x,y) implies(not(x),or(y,z)) -> implies(y,or(x,z)) implies(x,or(y,z)) -> or(y,implies(x,z)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: implies#(not(x),or(y,z)) -> implies#(y,or(x,z)) p2: implies#(x,or(y,z)) -> implies#(x,z) and R consists of: r1: implies(not(x),y) -> or(x,y) r2: implies(not(x),or(y,z)) -> implies(y,or(x,z)) r3: implies(x,or(y,z)) -> or(y,implies(x,z)) The estimated dependency graph contains the following SCCs: {p1, p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: implies#(not(x),or(y,z)) -> implies#(y,or(x,z)) p2: implies#(x,or(y,z)) -> implies#(x,z) and R consists of: r1: implies(not(x),y) -> or(x,y) r2: implies(not(x),or(y,z)) -> implies(y,or(x,z)) r3: implies(x,or(y,z)) -> or(y,implies(x,z)) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: implies#_A(x1,x2) = max{0, x2 - 5} not_A(x1) = max{1, x1} or_A(x1,x2) = x2 + 6 precedence: implies# = not = or partial status: pi(implies#) = [] pi(not) = [1] pi(or) = [2] 2. weighted path order base order: max/plus interpretations on natural numbers: implies#_A(x1,x2) = 0 not_A(x1) = 2 or_A(x1,x2) = x2 + 5 precedence: implies# = not = or partial status: pi(implies#) = [] pi(not) = [] pi(or) = [2] The next rules are strictly ordered: p2 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: implies#(not(x),or(y,z)) -> implies#(y,or(x,z)) and R consists of: r1: implies(not(x),y) -> or(x,y) r2: implies(not(x),or(y,z)) -> implies(y,or(x,z)) r3: implies(x,or(y,z)) -> or(y,implies(x,z)) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: implies#(not(x),or(y,z)) -> implies#(y,or(x,z)) and R consists of: r1: implies(not(x),y) -> or(x,y) r2: implies(not(x),or(y,z)) -> implies(y,or(x,z)) r3: implies(x,or(y,z)) -> or(y,implies(x,z)) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: implies#_A(x1,x2) = max{x1 + 2, x2 + 1} not_A(x1) = max{3, x1 + 2} or_A(x1,x2) = x1 + 2 precedence: implies# = not = or partial status: pi(implies#) = [] pi(not) = [1] pi(or) = [1] 2. weighted path order base order: max/plus interpretations on natural numbers: implies#_A(x1,x2) = 0 not_A(x1) = max{2, x1} or_A(x1,x2) = x1 + 3 precedence: implies# = not = or partial status: pi(implies#) = [] pi(not) = [1] pi(or) = [1] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.