doc-src/TutorialI/Protocol/ROOT.ML

remove redundant lemmas expi_add and expi_zero

(*
To update:
cp /home/lcp/isabelle/Repos/HOL/Auth/{Message.thy,Message_lemmas.ML,Event.thy,Event_lemmas.ML,Public.thy,Public_lemmas.ML,NS_Public.thy} .
*)

use_thy "NS_Public";