--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/IOA/ABP/Env.thy Thu Apr 13 16:55:14 1995 +0200
@@ -0,0 +1,47 @@
+(* Title: HOL/IOA/ABP/Impl.thy
+ ID: $Id$
+ Author: Tobias Nipkow & Konrad Slind
+ Copyright 1994 TU Muenchen
+
+The environment
+*)
+
+Env = IOA + Action +
+
+types
+
+'m env_state = "bool"
+(* give next bit to system *)
+
+consts
+
+env_asig :: "'m action signature"
+env_trans :: "('m action, 'm env_state)transition set"
+env_ioa :: "('m action, 'm env_state)ioa"
+next :: "'m env_state => bool"
+
+defs
+
+env_asig_def
+ "env_asig == ({Next}, \
+\ UN m. {S_msg(m)}, \
+\ {})"
+
+env_trans_def "env_trans == \
+\ {tr. let s = fst(tr); \
+\ t = snd(snd(tr)) \
+\ in case fst(snd(tr)) \
+\ of \
+\ Next => t=True | \
+\ S_msg(m) => s=True & t=False | \
+\ R_msg(m) => False | \
+\ S_pkt(pkt) => False | \
+\ R_pkt(pkt) => False | \
+\ S_ack(b) => False | \
+\ R_ack(b) => False}"
+
+env_ioa_def "env_ioa == \
+\ (env_asig, {True}, env_trans)"
+
+end
+