removed checkpoint interface;
moved back to copy/checkpoint instead of checkpoint/checkpoint
(NB 1: checkpoint is idempotent, i.e. impure data is being shared, which is inappropriate;
NB 2: copying a checkpoint always produces a related theory);
present_proof: proper treatment of history;
tuned;
(* $Id$ *)
time_use_thy "Mutil";
time_use_thy "QuoDataType";
time_use_thy "QuoNestedDataType";
time_use_thy "Term";
time_use_thy "ABexp";
time_use_thy "Tree";
time_use_thy "Ordinals";
time_use_thy "Sigma_Algebra";
time_use_thy "Comb";
time_use_thy "PropLog";
time_use_thy "SList";
time_use_thy "LFilter";