Termination of the given GTRS could be disproven:

(0) Obligation:

Generalized rewrite system (where rules with free variables on rhs are allowed):
The TRS R consists of the following rules:

if(true) → X
if(false) → Y
minus → 0
minus → minus
geq → true
geq → false
geq → geq
div(0) → 0
div(s(X)) → if(geq)

(1) CritRuleProof (EQUIVALENT transformation)

The rule if(true) → X contains free variables in its right-hand side. Hence the TRS is not-terminating.

(2) FALSE