Termination Proof Script

Consider the TRS R consisting of the rewrite rules
1:    ack(0,y)  → s(y)
2:    ack(s(x),0)  → ack(x,s(0))
3:    ack(s(x),s(y))  → ack(x,ack(s(x),y))
4:    f(s(x),y)  → f(x,s(x))
5:    f(x,s(y))  → f(y,x)
6:    f(x,y)  → ack(x,y)
7:    ack(s(x),y)  → f(x,x)
There are 7 dependency pairs:
8:    ACK(s(x),0)  → ACK(x,s(0))
9:    ACK(s(x),s(y))  → ACK(x,ack(s(x),y))
10:    ACK(s(x),s(y))  → ACK(s(x),y)
11:    F(s(x),y)  → F(x,s(x))
12:    F(x,s(y))  → F(y,x)
13:    F(x,y)  → ACK(x,y)
14:    ACK(s(x),y)  → F(x,x)
Consider the SCC {8-14}. The constraints could not be solved.
Tyrolean Termination Tool  (0.02 seconds)   ---  May 3, 2006