let rec is_dummy_term = function
If_const(i) ->
(match (string_id#get_name i) with
"dummy_agent"
| "dummy_nat"
| "dummy_bool"
| "dummy_hash"
| "dummy_msg"
| "dummy_nonce"
| "dummy_pk"
| "dummy_sk"
| "dummy_chnl"
| "dummy_chnl_ota"
| "dummy_chnl_dy"
| "dummy_pid"
| "dummy_func"
| "dummy_set"
| "dummy_list" -> true
| _ -> false)
| If_pair(t1,t2)
| If_crypt(t1,t2)
| If_scrypt(t1,t2) -> (is_dummy_term t1) || (is_dummy_term t2)
| If_inv(t) -> is_dummy_term t
| _ -> false