Nuprl Lemma : singleton-type-product
∀[A,B:Type].  (singleton-type(A) 
⇒ singleton-type(B) 
⇒ singleton-type(A × B))
Proof
Definitions occuring in Statement : 
singleton-type: singleton-type(A)
, 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
product: x:A × B[x]
, 
universe: Type
Definitions unfolded in proof : 
singleton-type: singleton-type(A)
, 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
exists: ∃x:A. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
guard: {T}
Lemmas referenced : 
all_wf, 
equal_wf, 
exists_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
lambdaFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
rename, 
dependent_pairFormation, 
independent_pairEquality, 
hypothesisEquality, 
cut, 
hypothesis, 
productEquality, 
lemma_by_obid, 
isectElimination, 
lambdaEquality, 
universeEquality, 
dependent_functionElimination
Latex:
\mforall{}[A,B:Type].    (singleton-type(A)  {}\mRightarrow{}  singleton-type(B)  {}\mRightarrow{}  singleton-type(A  \mtimes{}  B))
Date html generated:
2016_05_14-PM-04_02_10
Last ObjectModification:
2015_12_26-PM-07_43_05
Theory : equipollence!!cardinality!
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