YES Termination w.r.t. Q proof of /home/cern_httpd/provide/research/cycsrs/tpdb/TPDB-d9b80194f163/SRS_Standard/Zantema_06/while2.srs

(0) Obligation:

Q restricted rewrite system:
The TRS R consists of the following rules:

a(b(x)) → d(x)
b(a(x)) → a(b(x))
d(c(x)) → f(a(b(b(c(x)))))
d(f(x)) → f(a(b(x)))
a(f(x)) → a(x)

Q is empty.

(1) RFCMatchBoundsTRSProof (EQUIVALENT transformation)

Termination of the TRS R could be shown with a Match Bound [MATCHBOUNDS1,MATCHBOUNDS2] of 2. This implies Q-termination of R.
The following rules were used to construct the certificate:

a(b(x)) → d(x)
b(a(x)) → a(b(x))
d(c(x)) → f(a(b(b(c(x)))))
d(f(x)) → f(a(b(x)))
a(f(x)) → a(x)

The certificate found is represented by the following graph.

The certificate consists of the following enumerated nodes:

2, 4, 16, 17, 18, 19, 20, 21, 22, 23, 24

Node 2 is start node and node 4 is final node.

Those nodes are connected through the following edges:

  • 2 to 4 labelled d_1(0), a_1(0), d_1(1), a_1(1)
  • 2 to 16 labelled a_1(0)
  • 2 to 17 labelled f_1(0)
  • 2 to 2 labelled f_1(0)
  • 2 to 21 labelled f_1(1), a_1(1), a_1(2)
  • 4 to 4 labelled #_1(0)
  • 16 to 4 labelled b_1(0), d_1(2)
  • 16 to 22 labelled a_1(1)
  • 16 to 23 labelled d_1(2)
  • 16 to 21 labelled f_1(1), a_1(2)
  • 17 to 18 labelled a_1(0)
  • 17 to 19 labelled d_1(1)
  • 18 to 19 labelled b_1(0)
  • 19 to 20 labelled b_1(0)
  • 20 to 4 labelled c_1(0)
  • 21 to 22 labelled a_1(1)
  • 21 to 23 labelled d_1(2)
  • 21 to 4 labelled d_1(2)
  • 21 to 21 labelled f_1(1), a_1(2)
  • 22 to 23 labelled b_1(1), d_1(2)
  • 22 to 4 labelled b_1(1), d_1(2)
  • 22 to 22 labelled a_1(1)
  • 22 to 21 labelled f_1(1), a_1(2)
  • 23 to 24 labelled b_1(1)
  • 24 to 4 labelled c_1(1)

(2) YES