X:Type, eq:EqDecider(X), f, g:x:X fp Type, x:X. f || g  f(x)?Void  g(x)?Top 

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Definitions	f || g, EqDecider(T), f(x)?z, Unit, P  Q, P & Q, x  dom(f), a:A fp B(a), , Prop, b, A, b, Top, f(x), x. t(x), x:A. B(x), P  Q, t  T
Lemmas	fpf-ap wf, assert wf, not wf, bnot wf, fpf-trivial-subtype-top, fpf-dom wf, assert of bnot, eqff to assert, iff transitivity, eqtt to assert, bool wf, top wf, fpf-cap wf, deq wf, fpf wf, fpf-compatible wf