Certification Problem

Input (TPDB TRS_Standard/CiME_04/boolean_rings)

The rewrite relation of the following TRS is considered.

xor(x,F) x (1)
xor(x,neg(x)) F (2)
and(x,T) x (3)
and(x,F) F (4)
and(x,x) x (5)
and(xor(x,y),z) xor(and(x,z),and(y,z)) (6)
xor(x,x) F (7)
impl(x,y) xor(and(x,y),xor(x,T)) (8)
or(x,y) xor(and(x,y),xor(x,y)) (9)
equiv(x,y) xor(x,xor(y,T)) (10)
neg(x) xor(x,T) (11)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by AProVE @ termCOMP 2023)

1 Rule Removal

Using the
prec(xor) = 0 stat(xor) = mul
prec(F) = 0 stat(F) = mul
prec(neg) = 1 stat(neg) = mul
prec(and) = 2 stat(and) = mul
prec(T) = 1 stat(T) = mul
prec(impl) = 3 stat(impl) = mul
prec(or) = 4 stat(or) = mul
prec(equiv) = 5 stat(equiv) = mul

π(xor) = [1,2]
π(F) = []
π(neg) = [1]
π(and) = [1,2]
π(T) = []
π(impl) = [1,2]
π(or) = [1,2]
π(equiv) = [1,2]

all of the following rules can be deleted.
xor(x,F) x (1)
xor(x,neg(x)) F (2)
and(x,T) x (3)
and(x,F) F (4)
and(x,x) x (5)
and(xor(x,y),z) xor(and(x,z),and(y,z)) (6)
xor(x,x) F (7)
impl(x,y) xor(and(x,y),xor(x,T)) (8)
or(x,y) xor(and(x,y),xor(x,y)) (9)
equiv(x,y) xor(x,xor(y,T)) (10)
neg(x) xor(x,T) (11)

1.1 R is empty

There are no rules in the TRS. Hence, it is terminating.