YES
  TPA v.1.0

Result: TRS is terminating

Default interpretations for symbols are not printed. For polynomial interpretations
and semantic labelling over N\{0,1} defaults are 2 for constants, identity for unary
symbols and x+y-2 for binary symbols. For semantic labelling over {0,1} (booleans)
defaults are 0 for constants, identity for unary symbols and disjunction for binary symbols.

[1]  TRS loaded from input file:
(1) f(f(X)) -> f(a(b(f(X))))
(2) f(a(g(X))) -> b(X)
(3) b(X) -> a(X)

[2]  Use following polynomial interpretation:
[g(x)] = x + 1
rest default

  Remove rules with left hand side strictly bigger than right hand side:
(2)

[3]  Label this TRS using following interpretation that is a model:
[f(x)] = 1
[a(x)] = 0
[b(x)] = 0
rest default

  thus obtaining new TRS:
(1a) f$1(f$1(X)) -> f$0(a$0(b$1(f$1(X))))
(1b) f$1(f$0(X)) -> f$0(a$0(b$1(f$0(X))))
(3a) b$1(X) -> a$1(X)
(3b) b$0(X) -> a$0(X)

[4]  Use following polynomial interpretation:
[b$0(x)] = x + 1
rest default

  Remove rules with left hand side strictly bigger than right hand side:
(3b)

[5]  Use following polynomial interpretation:
[f$1(x)] = x + 1
rest default

  Remove rules with left hand side strictly bigger than right hand side:
(1a)-(1b)

[6]  Use following polynomial interpretation:
[b$1(x)] = x + 1
rest default

  Remove rules with left hand side strictly bigger than right hand side:
(3a)

[7]  Since there are no remaining rules, termination is proved!

../tpdb/TRS/Rubio/p266.trs, 0., Y
Couldn't open file <60>: 60: No such file or directory