NO
Non-Confluence Proof
Non-Confluence Proof
by Hakusan
Input
The rewrite relation of the following TRS is considered.
| 
f(c) | 
→ | 
a | 
| 
f(a) | 
→ | 
c | 
| c | 
→ | 
f(h(a,h(f(c),c))) | 
| 
h(f(c),f(b)) | 
→ | 
f(h(a,c)) | 
Proof
1 Non-Joinable Fork
        The system is not confluent due to the following forking derivations.  
        
| t0
 | 
= | 
f(c) | 
 | 
→1
 | 
f(f(h(a,h(f(c),c)))) | 
 | 
= | 
t1
 | 
            
        The two resulting terms cannot be joined for the following reason:
        - When applying the cap-function on both terms (where variables may be treated like constants)
            then the resulting terms do not unify.
 
Tool configuration
Hakusan