fixed SPASS fact offset calculation and report unexpected unsound proofs with so-called sound encodings
(* Title: HOL/HOLCF/IOA/NTP/Packet.thy
Author: Tobias Nipkow & Konrad Slind
*)
theory Packet
imports Multiset
begin
type_synonym
'msg packet = "bool * 'msg"
definition
hdr :: "'msg packet => bool" where
"hdr == fst"
definition
msg :: "'msg packet => 'msg" where
"msg == snd"
text {* Instantiation of a tautology? *}
lemma eq_packet_imp_eq_hdr: "!x. x = packet --> hdr(x) = hdr(packet)"
by simp
declare hdr_def [simp] msg_def [simp]
end