(from Ste92 A.30)
(VAR x y z)
(RULES
le(0,y) -> true
le(s(x),0) -> false
le(s(x),s(y)) -> le(x,y)
eq(0,0) -> true
eq(0,s(y)) -> false
eq(s(x),0) -> false
eq(s(x),s(y)) -> eq(x,y)
if(true,x,y) -> x
if(false,x,y) -> y
minsort(nil) -> nil
minsort(cons(x,y)) -> cons(min(x,y),minsort(del(min(x,y),cons(x,y))))
min(x,nil) -> x
min(x,cons(y,z)) -> if(le(x,y),min(x,z),min(y,z))
del(x,nil) -> nil
del(x,cons(y,z)) -> if(eq(x,y),z,cons(y,del(x,z)))
)