# File Packet.ML

    (*  Title:      HOL/IOA/NTP/Packet.ML
        ID:         $Id: Packet.ML,v 1.6 2005/09/03 14:50:24 wenzelm Exp $
        Author:     Tobias Nipkow & Konrad Slind

    Packets.
    *)

    (* Instantiation of a tautology? *)
    Goal "!x. x = packet --> hdr(x) = hdr(packet)";
     by (simp_tac (simpset() addsimps [hdr_def]) 1);
    qed "eq_packet_imp_eq_hdr";

    Addsimps [hdr_def,msg_def];