doc-src/Intro/bool.thy

Sort search results in order of relevance, where relevance =
a) better if 0 premises for intro or 1 premise for elim/dest rules
b) better if substitution size wrt to current goal is smaller

Only applies to intro, dest, elim, and simp

(contributed by Rafal Kolanski, NICTA)

Bool = FOL +
types 	bool 0
arities bool 	:: term
consts tt,ff	:: "bool"
end