MAYBE

Initial complexity problem:
1:	T:
		(1, 1)    f0(a, b) -> f3(0, b)
		(?, 1)    f3(a, b) -> f3(c + 1, b) [ a = 5 ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ 4 >= a ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ a >= 6 ]
		(?, 1)    f3(a, b) -> f12(a, b) [ a >= 10 ]
	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) -> f3(0, b)
		(?, 1)    f3(a, b) -> f3(c + 1, b) [ a = 5 ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ 4 >= a ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ a >= 6 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b) -> f3(0, b) with all transitions in problem 2, the following new transition is obtained:
	f0(a, b) -> f3(1, 0) [ 9 >= 0 /\ 4 >= 0 ]
We thus obtain the following problem:
3:	T:
		(1, 2)    f0(a, b) -> f3(1, 0) [ 9 >= 0 /\ 4 >= 0 ]
		(?, 1)    f3(a, b) -> f3(c + 1, b) [ a = 5 ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ 4 >= a ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ a >= 6 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b) -> f3(1, 0) [ 9 >= 0 /\ 4 >= 0 ] with all transitions in problem 3, the following new transition is obtained:
	f0(a, b) -> f3(2, 1) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 ]
We thus obtain the following problem:
4:	T:
		(1, 3)    f0(a, b) -> f3(2, 1) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 ]
		(?, 1)    f3(a, b) -> f3(c + 1, b) [ a = 5 ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ 4 >= a ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ a >= 6 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b) -> f3(2, 1) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 ] with all transitions in problem 4, the following new transition is obtained:
	f0(a, b) -> f3(3, 2) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 /\ 9 >= 2 /\ 4 >= 2 ]
We thus obtain the following problem:
5:	T:
		(1, 4)    f0(a, b) -> f3(3, 2) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 /\ 9 >= 2 /\ 4 >= 2 ]
		(?, 1)    f3(a, b) -> f3(c + 1, b) [ a = 5 ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ 4 >= a ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ a >= 6 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b) -> f3(3, 2) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 /\ 9 >= 2 /\ 4 >= 2 ] with all transitions in problem 5, the following new transition is obtained:
	f0(a, b) -> f3(4, 3) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 /\ 9 >= 2 /\ 4 >= 2 /\ 9 >= 3 /\ 4 >= 3 ]
We thus obtain the following problem:
6:	T:
		(1, 5)    f0(a, b) -> f3(4, 3) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 /\ 9 >= 2 /\ 4 >= 2 /\ 9 >= 3 /\ 4 >= 3 ]
		(?, 1)    f3(a, b) -> f3(c + 1, b) [ a = 5 ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ 4 >= a ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ a >= 6 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b) -> f3(4, 3) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 /\ 9 >= 2 /\ 4 >= 2 /\ 9 >= 3 /\ 4 >= 3 ] with all transitions in problem 6, the following new transition is obtained:
	f0(a, b) -> f3(5, 4) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 /\ 9 >= 2 /\ 4 >= 2 /\ 9 >= 3 /\ 4 >= 3 /\ 9 >= 4 /\ 4 >= 4 ]
We thus obtain the following problem:
7:	T:
		(1, 6)    f0(a, b) -> f3(5, 4) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 /\ 9 >= 2 /\ 4 >= 2 /\ 9 >= 3 /\ 4 >= 3 /\ 9 >= 4 /\ 4 >= 4 ]
		(?, 1)    f3(a, b) -> f3(c + 1, b) [ a = 5 ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ 4 >= a ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ a >= 6 ]
	start location:	f0
	leaf cost:	1

By chaining the transition f0(a, b) -> f3(5, 4) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 /\ 9 >= 2 /\ 4 >= 2 /\ 9 >= 3 /\ 4 >= 3 /\ 9 >= 4 /\ 4 >= 4 ] with all transitions in problem 7, the following new transition is obtained:
	f0(a, b) -> f3(c + 1, 4) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 /\ 9 >= 2 /\ 4 >= 2 /\ 9 >= 3 /\ 4 >= 3 /\ 9 >= 4 /\ 4 >= 4 /\ 5 = 5 ]
We thus obtain the following problem:
8:	T:
		(1, 7)    f0(a, b) -> f3(c + 1, 4) [ 9 >= 0 /\ 4 >= 0 /\ 9 >= 1 /\ 4 >= 1 /\ 9 >= 2 /\ 4 >= 2 /\ 9 >= 3 /\ 4 >= 3 /\ 9 >= 4 /\ 4 >= 4 /\ 5 = 5 ]
		(?, 1)    f3(a, b) -> f3(c + 1, b) [ a = 5 ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ 4 >= a ]
		(?, 1)    f3(a, b) -> f3(a + 1, a) [ 9 >= a /\ a >= 6 ]
	start location:	f0
	leaf cost:	1

Complexity upper bound ?

Time: 0.502 sec (SMT: 0.468 sec)