propp: 'concl' patterns;
assumptions: tactics for non-goal export;
use Display.pretty_thm_no_hyps;
assm vs. assume vs. presume;
tuned type goal;
tuned print_goal;
relative exports, absolute export_thm rule;
transfer_facts;
tuned;
Fib = WF_Rel +
consts fib :: nat => nat
recdef fib "measure(%n. n)"
"fib 0 = 0"
"fib 1 = 1"
"fib (Suc(Suc x)) = fib x + fib (Suc x)"
end