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: ℕ
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
not: ¬A
, 
implies: P 
⇒ 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: P 
⇒ Q
, 
not: ¬A
, 
false: False
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
and: P ∧ Q
, 
subtype_rel: A ⊆r B
, 
or: P ∨ Q
, 
all: ∀x:A. B[x]
, 
nat: ℕ
, 
exists: ∃x:A. B[x]
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
weakly-infinite: w∃∞p.S[p]
, 
iff: P 
⇐⇒ Q
, 
guard: {T}
, 
decidable: Dec(P)
, 
cand: A c∧ B
, 
le: A ≤ B
, 
rev_implies: P 
⇐ Q
, 
subtract: n - 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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