Nuprl Lemma : weakly-infinite-cases

[S:ℕ ⟶ ℙ]. (w∃∞x.S[x]  (∀[A:ℕ ⟶ ℙ]. ((∀n:ℕ(A[n]  S[n]))  (¬¬(w∃∞n.A[n] ∨ w∃∞n.S[n] ∧ A[n]))))))


Proof




Definitions occuring in Statement :  weakly-infinite: w∃∞p.S[p] nat: uall: [x:A]. B[x] prop: so_apply: x[s] all: x:A. B[x] not: ¬A implies:  Q or: P ∨ Q and: P ∧ Q function: x:A ⟶ B[x]
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T implies:  Q not: ¬A false: False prop: so_lambda: λ2x.t[x] so_apply: x[s] and: P ∧ Q subtype_rel: A ⊆B or: P ∨ Q all: x:A. B[x] nat: exists: x:A. B[x] uiff: uiff(P;Q) uimplies: supposing a weakly-infinite: w∃∞p.S[p] iff: ⇐⇒ Q guard: {T} decidable: Dec(P) cand: c∧ B le: A ≤ B rev_implies:  Q subtract: m top: Top less_than': less_than'(a;b) true: True
Lemmas referenced :  not_wf or_wf weakly-infinite_wf nat_wf all_wf false_wf exists_wf less_than_wf not_over_exists minimal-double-negation-hyp-elim minimal-not-not-excluded-middle dneg_elim_a double-negation-hyp-elim decidable__le le_weakening le_wf le_reflexive not-le-2 condition-implies-le minus-add minus-one-mul add-swap minus-one-mul-top add-commutes add_functionality_wrt_le add-associates le-add-cancel less_than_transitivity2
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation introduction cut lambdaFormation thin hypothesis sqequalHypSubstitution independent_functionElimination voidElimination extract_by_obid isectElimination sqequalRule lambdaEquality applyEquality functionExtensionality hypothesisEquality productEquality universeEquality functionEquality dependent_functionElimination because_Cache cumulativity isect_memberEquality inlFormation setElimination rename productElimination independent_isectElimination unionElimination dependent_pairFormation addLevel impliesFunctionality levelHypothesis inrFormation independent_pairFormation addEquality natural_numberEquality voidEquality intEquality minusEquality promote_hyp

Latex:
\mforall{}[S:\mBbbN{}  {}\mrightarrow{}  \mBbbP{}]
    (w\mexists{}\minfty{}x.S[x]  {}\mRightarrow{}  (\mforall{}[A:\mBbbN{}  {}\mrightarrow{}  \mBbbP{}].  ((\mforall{}n:\mBbbN{}.  (A[n]  {}\mRightarrow{}  S[n]))  {}\mRightarrow{}  (\mneg{}\mneg{}(w\mexists{}\minfty{}n.A[n]  \mvee{}  w\mexists{}\minfty{}n.S[n]  \mwedge{}  (\mneg{}A[n]))))))



Date html generated: 2017_09_29-PM-05_47_37
Last ObjectModification: 2017_07_26-PM-01_25_15

Theory : bar-induction


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