--- /dev/null
+(**************************************************************************)
+(* ___ *)
+(* ||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/formal_topology/".
+include "logic/equality.ma".
+
+axiom S: Type.
+
+axiom comp: S → S → S.
+coercion cic:/matita/formal_topology/comp.con 1.
+
+axiom comp_assoc: ∀A,B,C:S. A (B C) = (A B) C.
+
+axiom one: S.
+
+notation "1" with precedence 89
+for @{ 'unit }.
+
+interpretation "Unit" 'unit =
+ cic:/matita/formal_topology/one.con.
+
+axiom one_left: ∀A. 1 A = A.
+axiom one_right: ∀A:S. A 1 = A.
+
+axiom eps: S.
+axiom eps_idempotent: eps = eps eps.
+
+notation "hvbox(A break ⊆ B)" with precedence 59
+for @{ 'subseteq $A $B}.
+
+interpretation "Subseteq" 'subseteq A B =
+ (cic:/matita/logic/equality/eq.ind#xpointer(1/1) _ A
+ (cic:/matita/formal_topology/comp.con
+ cic:/matita/formal_topology/eps.con B)).
+
+axiom leq_refl: ∀A. A ⊆ A.
+axiom leq_antisym: ∀A,B. A ⊆ B → B ⊆ A → A=B.
+axiom leq_tran: ∀A,B,C. A ⊆ B → B ⊆ C → A ⊆ C.
+
+axiom i: S.
+
+axiom i_contrattivita: i ⊆ 1.
+axiom i_idempotenza: i i = i.
+axiom i_monotonia: ∀A,B. A ⊆ B → i A ⊆ i B.
+
+axiom c: S.
+
+axiom c_espansivita: 1 ⊆ c.
+axiom c_idempotenza: c c = c.
+axiom c_monotonia: ∀A,B. A ⊆ B → c A ⊆ c B.
+
+axiom m: S.
+
+axiom m_antimonotonia: ∀A,B. A ⊆ B → m B ⊆ m A.
+axiom m_saturazione: 1 ⊆ m m.
+axiom m_puntofisso: m = m (m m).
+
+theorem th1: c m ⊆ m i. intros; auto. qed.
+theorem th2: ∀A. i (m A) ⊆ (m (c A)). intros; auto. qed.
+theorem th3: ∀A. i A ⊆ (m (c (m A))). intros; auto. qed.
+theorem th4: ∀A. c A ⊆ (m (i (m A))). intros; auto. qed.
+
+theorem th5: ∀A. i (m A) = i (m (c A)). intros; auto. qed.
+theorem th6: ∀A. m (i A) = c (m (i A)). intros; auto. qed.
+
+theorem th7: ∀A. i (m (i A)) = i (s (i A)).
\ No newline at end of file