2 ||M|| This file is part of HELM, an Hypertextual, Electronic
3 ||A|| Library of Mathematics, developed at the Computer Science
4 ||T|| Department, University of Bologna, Italy.
6 ||T|| HELM is free software; you can redistribute it and/or
7 ||A|| modify it under the terms of the GNU General Public License
8 \ / version 2 or (at your option) any later version.
9 \ / This software is distributed as is, NO WARRANTY.
10 V_______________________________________________________________ *)
17 | Node of ('a foterm) list
19 type 'a substitution = (int * 'a foterm) list
21 type comparison = Lt | Eq | Gt | Incomparable
23 type rule = SuperpositionRight | SuperpositionLeft | Demodulation
24 type direction = Left2Right | Right2Left | Nodir
25 type position = int list
29 (* for theorems like T : \forall x. C[x] = D[x] the proof is
30 * a foterm like (Node [ Leaf T ; Var i ]), while for the Goal
31 * it is just (Var g), i.e. the identity proof *)
32 | Step of rule * int * int * direction * position * 'a substitution
33 (* rule, eq1, eq2, direction of eq2, position, substitution *)
36 | Equation of 'a foterm (* lhs *)
38 * 'a foterm (* type *)
39 * comparison (* orientation *)
40 | Predicate of 'a foterm
42 type varlist = int list
48 * 'a proof (* proof *)
50 type 'a passive_clause = int * 'a unit_clause (* weight * equation *)
52 module M : Map.S with type key = int
54 type 'a bag = 'a unit_clause M.t
58 (* Blob is the type for opaque leaves:
59 * - checking equlity should be efficient
60 * - atoms have to be equipped with a total order relation
63 val eq : t -> t -> bool
64 val compare : t -> t -> int
65 val is_eq_predicate : t -> bool
66 (* TODO: consider taking in input an imperative buffer for Format
67 * val pp : Format.formatter -> t -> unit
71 val embed : t -> t foterm
72 (* saturate [proof] [type] -> [proof] * [type] *)
73 val saturate : t -> t -> t foterm * t foterm