make Sledgehammer "minimize" output less confusing + round up (not down) time limits to nearest second
(*  Title:      HOL/IOA/NTP/Packet.thy
    Author:     Tobias Nipkow & Konrad Slind
*)
theory Packet
imports Multiset
begin
types
  '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