YES

proof:
The input problem is infeasible because

[1] the following set of Horn clauses is satisfiable:

	+(s(x), y) = s(+(x, y))
	+(0, x) = x
	+(x, a) = 0 ==> true__ = false__
	true__ = false__ ==> \bottom

This holds because

[2] the following E does not entail the following G (Claessen-Smallbone's transformation (2018)):

E:
	+(0, x) = x
	+(s(x), y) = s(+(x, y))
	t1(+(x, a)) = true__
	t1(0) = false__
	t2(false__) = true__
	t2(true__) = false__
G:
	true__ = false__

This holds because

[3] the following ground-complete ordered TRS entails E but does not entail G:

	t1(0) -> false__
	t1(a) -> true__
	t2(false__) -> true__
	t2(true__) -> false__
with the LPO induced by
	t2 > a > t1 > 0 > + > s > false__ > true__
with the following interpretations:
	+ returns 2nd variable
	s returns 1st variable