refactoring

[helm.git] / matita / contribs / LOGIC / datatypes_defs / Sequent.ma

diff --git a/matita/contribs/LOGIC/datatypes_defs/Sequent.ma b/matita/contribs/LOGIC/datatypes_defs/Sequent.ma
new file mode 100644 (file)
index 0000000..09d8269
--- /dev/null
+++ b/matita/contribs/LOGIC/datatypes_defs/Sequent.ma
@@ -0,0 +1,46 @@
+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||M||                                                             *)
+(*      ||A||       A project by Andrea Asperti                           *)
+(*      ||T||                                                             *)
+(*      ||I||       Developers:                                           *)
+(*      ||T||         The HELM team.                                      *)
+(*      ||A||         http://helm.cs.unibo.it                             *)
+(*      \   /                                                             *)
+(*       \ /        This file is distributed under the terms of the       *)
+(*        v         GNU General Public License Version 2                  *)
+(*                                                                        *)
+(**************************************************************************)
+
+set "baseuri" "cic:/matita/LOGIC/datatypes_defs/Sequent".
+
+(* SEQUENTS
+   - Naming policy:
+     - left hand sides  (lhs): A C
+     - right hand sides (rhs): B D
+     - sequents              : R S
+*)
+
+include "datatypes_defs/Formula.ma".
+
+inductive LHS: Type \def
+   | lleaf: LHS
+   | labst: LHS \to Formula \to LHS
+.
+
+inductive RHS: Type \def
+   | rleaf: RHS
+   | rabst: Formula \to RHS \to RHS
+.
+
+inductive Sequent: Type \def
+   | pair: LHS \to RHS \to Sequent
+.
+
+definition linj: Formula \to LHS \def labst lleaf.
+
+definition rinj: Formula \to RHS \def \lambda b. rabst b rleaf.
+
+coercion cic:/matita/LOGIC/datatypes_defs/Sequent/linj.con.
+
+coercion cic:/matita/LOGIC/datatypes_defs/Sequent/rinj.con.