Nuprl Lemma : k-ext-iff
∀[k:ℕ]. ∀[A,B:ℕk ⟶ Type].  uiff(A ≡ B;∀i:ℕk. A i ≡ B i)
Proof
Definitions occuring in Statement : 
k-ext: A ≡ B
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
ext-eq: A ≡ B
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
, 
universe: Type
Definitions unfolded in proof : 
k-ext: A ≡ B
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
all: ∀x:A. B[x]
, 
ext-eq: A ≡ B
, 
k-subtype: A ⊆ B
, 
nat: ℕ
, 
subtype_rel: A ⊆r B
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
Lemmas referenced : 
int_seg_wf, 
k-subtype_wf, 
all_wf, 
ext-eq_wf, 
nat_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
introduction, 
cut, 
independent_pairFormation, 
lambdaFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
hypothesis, 
dependent_functionElimination, 
hypothesisEquality, 
extract_by_obid, 
isectElimination, 
natural_numberEquality, 
setElimination, 
rename, 
lambdaEquality, 
independent_pairEquality, 
axiomEquality, 
because_Cache, 
productEquality, 
functionExtensionality, 
applyEquality, 
isect_memberEquality, 
equalityTransitivity, 
equalitySymmetry, 
functionEquality, 
cumulativity, 
universeEquality
Latex:
\mforall{}[k:\mBbbN{}].  \mforall{}[A,B:\mBbbN{}k  {}\mrightarrow{}  Type].    uiff(A  \mequiv{}  B;\mforall{}i:\mBbbN{}k.  A  i  \mequiv{}  B  i)
Date html generated:
2018_05_21-PM-00_09_03
Last ObjectModification:
2017_10_18-PM-02_32_19
Theory : co-recursion
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