YES Problem: or(x,x) -> x and(x,x) -> x not(not(x)) -> x not(and(x,y)) -> or(not(x),not(y)) not(or(x,y)) -> and(not(x),not(y)) Proof: DP Processor: DPs: not#(and(x,y)) -> not#(y) not#(and(x,y)) -> not#(x) not#(and(x,y)) -> or#(not(x),not(y)) not#(or(x,y)) -> not#(y) not#(or(x,y)) -> not#(x) not#(or(x,y)) -> and#(not(x),not(y)) TRS: or(x,x) -> x and(x,x) -> x not(not(x)) -> x not(and(x,y)) -> or(not(x),not(y)) not(or(x,y)) -> and(not(x),not(y)) KBO Processor: argument filtering: pi(or) = [0,1] pi(and) = [0,1] pi(not) = [0] pi(or#) = 0 pi(and#) = 0 pi(not#) = 0 weight function: w0 = 1 w(not#) = w(or#) = 1 w(and#) = w(not) = w(and) = w(or) = 0 precedence: or# > not > not# ~ and# ~ and ~ or problem: DPs: TRS: or(x,x) -> x and(x,x) -> x not(not(x)) -> x not(and(x,y)) -> or(not(x),not(y)) not(or(x,y)) -> and(not(x),not(y)) Qed