Nuprl Lemma : not-l_exists

[T:Type]. ∀L:T List. ∀[P:{x:T| (x ∈ L)}  ⟶ ℙ]. (∃x∈L. P[x]) ⇐⇒ (∀x∈L.¬P[x]))


Proof




Definitions occuring in Statement :  l_exists: (∃x∈L. P[x]) l_all: (∀x∈L.P[x]) l_member: (x ∈ l) list: List uall: [x:A]. B[x] prop: so_apply: x[s] all: x:A. B[x] iff: ⇐⇒ Q not: ¬A set: {x:A| B[x]}  function: x:A ⟶ B[x] universe: Type
Definitions unfolded in proof :  iff: ⇐⇒ Q and: P ∧ Q implies:  Q all: x:A. B[x] not: ¬A false: False member: t ∈ T prop: so_apply: x[s] uall: [x:A]. B[x] so_lambda: λ2x.t[x] subtype_rel: A ⊆B rev_implies:  Q uiff: uiff(P;Q) uimplies: supposing a exists: x:A. B[x] guard: {T} int_seg: {i..j-} sq_stable: SqStable(P) lelt: i ≤ j < k squash: T l_all: (∀x∈L.P[x]) cand: c∧ B
Lemmas referenced :  list_wf length_wf int_seg_wf sq_stable__le list-subtype select_wf l_all_wf l_exists_wf l_all_iff l_exists_iff iff_wf exists_wf not_over_exists not_wf all_wf l_member_wf
Rules used in proof :  cut sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity independent_pairFormation lambdaFormation thin because_Cache hypothesis sqequalHypSubstitution independent_functionElimination voidElimination applyEquality hypothesisEquality dependent_set_memberEquality lemma_by_obid isectElimination cumulativity sqequalRule lambdaEquality productEquality productElimination functionEquality addLevel impliesFunctionality independent_isectElimination universeEquality dependent_functionElimination setEquality impliesLevelFunctionality equalityTransitivity equalitySymmetry setElimination rename natural_numberEquality introduction imageMemberEquality baseClosed imageElimination isect_memberFormation independent_pairEquality isect_memberEquality

Latex:
\mforall{}[T:Type].  \mforall{}L:T  List.  \mforall{}[P:\{x:T|  (x  \mmember{}  L)\}    {}\mrightarrow{}  \mBbbP{}].  (\mneg{}(\mexists{}x\mmember{}L.  P[x])  \mLeftarrow{}{}\mRightarrow{}  (\mforall{}x\mmember{}L.\mneg{}P[x]))



Date html generated: 2016_05_14-AM-06_40_52
Last ObjectModification: 2016_01_14-PM-08_20_13

Theory : list_0


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