Nuprl Lemma : can-apply-p-lift

[A,B:Type]. ∀[P:A ⟶ ℙ].  ∀d:x:A ⟶ Dec(P[x]). ∀f:{x:A| P[x]}  ⟶ B. ∀x:A.  (↑can-apply(p-lift(d;f);x) ⇐⇒ P[x])


Proof




Definitions occuring in Statement :  p-lift: p-lift(d;f) can-apply: can-apply(f;x) assert: b decidable: Dec(P) uall: [x:A]. B[x] prop: so_apply: x[s] all: x:A. B[x] iff: ⇐⇒ Q set: {x:A| B[x]}  function: x:A ⟶ B[x] universe: Type
Definitions unfolded in proof :  p-lift: p-lift(d;f) can-apply: can-apply(f;x) uall: [x:A]. B[x] all: x:A. B[x] member: t ∈ T so_apply: x[s] subtype_rel: A ⊆B prop: implies:  Q decidable: Dec(P) or: P ∨ Q isl: isl(x) assert: b ifthenelse: if then else fi  btrue: tt iff: ⇐⇒ Q and: P ∧ Q rev_implies:  Q true: True bfalse: ff false: False not: ¬A
Lemmas referenced :  decidable_wf true_wf false_wf equal_wf
Rules used in proof :  sqequalSubstitution sqequalRule sqequalReflexivity sqequalTransitivity computationStep isect_memberFormation lambdaFormation hypothesisEquality functionEquality setEquality cut applyEquality hypothesis thin lambdaEquality sqequalHypSubstitution universeEquality lemma_by_obid isectElimination cumulativity unionElimination independent_pairFormation natural_numberEquality voidElimination independent_functionElimination equalityTransitivity equalitySymmetry dependent_functionElimination

Latex:
\mforall{}[A,B:Type].  \mforall{}[P:A  {}\mrightarrow{}  \mBbbP{}].
    \mforall{}d:x:A  {}\mrightarrow{}  Dec(P[x]).  \mforall{}f:\{x:A|  P[x]\}    {}\mrightarrow{}  B.  \mforall{}x:A.    (\muparrow{}can-apply(p-lift(d;f);x)  \mLeftarrow{}{}\mRightarrow{}  P[x])



Date html generated: 2016_05_15-PM-03_29_20
Last ObjectModification: 2015_12_27-PM-01_09_31

Theory : general


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