--- From maude docs
--- This is a comment.
*** This is a comment too.
fmod SIMPLE-NAT is
sort Nat .
op zero : -> Nat .
op s_ : Nat -> Nat .
op _+_ : Nat Nat -> Nat .
--- variables
vars N M : Nat .
--- rewrite rules
eq zero + N = N .
eq s N + M = s (N + M) .
endfm