(VAR u v x y )
(STRATEGY INNERMOST)
(RULES 
        minus(x,y) -> cond(equal(min(x,y),y),x,y)
        cond(true,x,y) -> s(minus(x,s(y)))
        min(0,v) -> 0
        min(u,0) -> 0
        min(s(u),s(v)) -> s(min(u,v))
        equal(0,0) -> true
        equal(s(x),0) -> false
        equal(0,s(y)) -> false
        equal(s(x),s(y)) -> equal(x,y)
        
)