MAYBE

Initial complexity problem:
1:	T:
		(?, 1)    f4(a, b, c) -> f5(a, b, c) [ a >= b + 1 ]
		(1, 1)    f0(a, b, c) -> f4(d, d + 1, b)
		(?, 1)    f4(a, b, c) -> f4(d, d + 1, b)
	start location:	f0
	leaf cost:	0

Repeatedly removing leaves of the complexity graph in problem 1 produces the following problem:
2:	T:
		(1, 1)    f0(a, b, c) -> f4(d, d + 1, b)
		(?, 1)    f4(a, b, c) -> f4(d, d + 1, b)
	start location:	f0
	leaf cost:	1

Applied AI with 'oct' on problem 2 to obtain the following invariants:
  For symbol f4: X_1 - X_2 + 1 >= 0 /\ -X_1 + X_2 - 1 >= 0


This yielded the following problem:
3:	T:
		(?, 1)    f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
		(1, 1)    f0(a, b, c) -> f4(d, d + 1, b)
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d, d + 1, b) with all transitions in problem 3, the following new transition is obtained:
	f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ]
We thus obtain the following problem:
4:	T:
		(1, 2)    f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ]
		(?, 1)    f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ] with all transitions in problem 4, the following new transition is obtained:
	f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ]
We thus obtain the following problem:
5:	T:
		(1, 3)    f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ]
		(?, 1)    f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ] with all transitions in problem 5, the following new transition is obtained:
	f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ]
We thus obtain the following problem:
6:	T:
		(1, 4)    f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ]
		(?, 1)    f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ] with all transitions in problem 6, the following new transition is obtained:
	f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ]
We thus obtain the following problem:
7:	T:
		(1, 5)    f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ]
		(?, 1)    f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ] with all transitions in problem 7, the following new transition is obtained:
	f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ]
We thus obtain the following problem:
8:	T:
		(1, 6)    f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ]
		(?, 1)    f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ] with all transitions in problem 8, the following new transition is obtained:
	f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ]
We thus obtain the following problem:
9:	T:
		(1, 7)    f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ]
		(?, 1)    f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ] with all transitions in problem 9, the following new transition is obtained:
	f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ]
We thus obtain the following problem:
10:	T:
		(1, 8)    f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ]
		(?, 1)    f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ] with all transitions in problem 10, the following new transition is obtained:
	f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ]
We thus obtain the following problem:
11:	T:
		(1, 9)    f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ]
		(?, 1)    f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ] with all transitions in problem 11, the following new transition is obtained:
	f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ]
We thus obtain the following problem:
12:	T:
		(1, 10)    f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ]
		(?, 1)     f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ] with all transitions in problem 12, the following new transition is obtained:
	f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ]
We thus obtain the following problem:
13:	T:
		(1, 11)    f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ]
		(?, 1)     f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ] with all transitions in problem 13, the following new transition is obtained:
	f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ]
We thus obtain the following problem:
14:	T:
		(1, 12)    f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ]
		(?, 1)     f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ] with all transitions in problem 14, the following new transition is obtained:
	f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ]
We thus obtain the following problem:
15:	T:
		(1, 13)    f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ]
		(?, 1)     f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ] with all transitions in problem 15, the following new transition is obtained:
	f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ]
We thus obtain the following problem:
16:	T:
		(1, 14)    f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ]
		(?, 1)     f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d', d' + 1, d + 1) [ 0 >= 0 ] with all transitions in problem 16, the following new transition is obtained:
	f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ]
We thus obtain the following problem:
17:	T:
		(1, 15)    f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ]
		(?, 1)     f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b, c) -> f4(d'', d'' + 1, d' + 1) [ 0 >= 0 ] with all transitions in problem 17, the following new transition is obtained:
	f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ]
We thus obtain the following problem:
18:	T:
		(1, 16)    f0(a, b, c) -> f4(d, d + 1, d'' + 1) [ 0 >= 0 ]
		(?, 1)     f4(a, b, c) -> f4(d, d + 1, b) [ a - b + 1 >= 0 /\ -a + b - 1 >= 0 ]
	start location:	f0
	leaf cost:	1

Complexity upper bound ?

Time: 0.671 sec (SMT: 0.620 sec)