YES(?, 2*a + 3*b + c + 2)

Initial complexity problem:
1:	T:
		(?, 1)    eval(a, b, c) -> eval(a - 1, b, c) [ a >= b + 1 ]
		(?, 1)    eval(a, b, c) -> eval(a - 1, b, c) [ c >= b + 1 /\ a >= b + 1 ]
		(?, 1)    eval(a, b, c) -> eval(a, b, c - 1) [ a >= b + 1 /\ b >= a /\ c >= b + 1 ]
		(?, 1)    eval(a, b, c) -> eval(a, b, c - 1) [ c >= b + 1 /\ b >= a ]
		(?, 1)    eval(a, b, c) -> eval(a, b, c) [ a >= b + 1 /\ b >= a /\ b >= c ]
		(?, 1)    eval(a, b, c) -> eval(a, b, c) [ c >= b + 1 /\ b >= a /\ b >= c ]
		(1, 1)    start(a, b, c) -> eval(a, b, c)
	start location:	start
	leaf cost:	0

Testing for unsatisfiable constraints removes the following transitions from problem 1:
	eval(a, b, c) -> eval(a, b, c - 1) [ a >= b + 1 /\ b >= a /\ c >= b + 1 ]
	eval(a, b, c) -> eval(a, b, c) [ a >= b + 1 /\ b >= a /\ b >= c ]
	eval(a, b, c) -> eval(a, b, c) [ c >= b + 1 /\ b >= a /\ b >= c ]
We thus obtain the following problem:
2:	T:
		(?, 1)    eval(a, b, c) -> eval(a - 1, b, c) [ a >= b + 1 ]
		(?, 1)    eval(a, b, c) -> eval(a - 1, b, c) [ c >= b + 1 /\ a >= b + 1 ]
		(?, 1)    eval(a, b, c) -> eval(a, b, c - 1) [ c >= b + 1 /\ b >= a ]
		(1, 1)    start(a, b, c) -> eval(a, b, c)
	start location:	start
	leaf cost:	0

A polynomial rank function with
	Pol(eval) = -V_2 + V_3 + 1
	Pol(start) = -V_2 + V_3 + 1
orients all transitions weakly and the transition
	eval(a, b, c) -> eval(a, b, c - 1) [ c >= b + 1 /\ b >= a ]
strictly and produces the following problem:
3:	T:
		(?, 1)            eval(a, b, c) -> eval(a - 1, b, c) [ a >= b + 1 ]
		(?, 1)            eval(a, b, c) -> eval(a - 1, b, c) [ c >= b + 1 /\ a >= b + 1 ]
		(b + c + 1, 1)    eval(a, b, c) -> eval(a, b, c - 1) [ c >= b + 1 /\ b >= a ]
		(1, 1)            start(a, b, c) -> eval(a, b, c)
	start location:	start
	leaf cost:	0

A polynomial rank function with
	Pol(eval) = V_1 - V_2
	Pol(start) = V_1 - V_2
orients all transitions weakly and the transitions
	eval(a, b, c) -> eval(a - 1, b, c) [ c >= b + 1 /\ a >= b + 1 ]
	eval(a, b, c) -> eval(a - 1, b, c) [ a >= b + 1 ]
strictly and produces the following problem:
4:	T:
		(a + b, 1)        eval(a, b, c) -> eval(a - 1, b, c) [ a >= b + 1 ]
		(a + b, 1)        eval(a, b, c) -> eval(a - 1, b, c) [ c >= b + 1 /\ a >= b + 1 ]
		(b + c + 1, 1)    eval(a, b, c) -> eval(a, b, c - 1) [ c >= b + 1 /\ b >= a ]
		(1, 1)            start(a, b, c) -> eval(a, b, c)
	start location:	start
	leaf cost:	0

Complexity upper bound 2*a + 3*b + c + 2

Time: 0.243 sec (SMT: 0.231 sec)