Nuprl Lemma : extend-type-equiv
∀[T:Type]. EquivRel(Base;x,y.(x ∈ T 
⇐⇒ y ∈ T) ∧ ((x ∈ T) 
⇒ (x = y ∈ T)))
Proof
Definitions occuring in Statement : 
equiv_rel: EquivRel(T;x,y.E[x; y])
, 
uall: ∀[x:A]. B[x]
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
member: t ∈ T
, 
base: Base
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
equiv_rel: EquivRel(T;x,y.E[x; y])
, 
and: P ∧ Q
, 
refl: Refl(T;x,y.E[x; y])
, 
all: ∀x:A. B[x]
, 
cand: A c∧ B
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
rev_implies: P 
⇐ Q
, 
sym: Sym(T;x,y.E[x; y])
, 
trans: Trans(T;x,y.E[x; y])
Lemmas referenced : 
istype-base, 
istype-universe
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
independent_pairFormation, 
Error :lambdaFormation_alt, 
sqequalHypSubstitution, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
sqequalRule, 
Error :equalityIstype, 
Error :universeIsType, 
hypothesisEquality, 
sqequalBase, 
because_Cache, 
productElimination, 
thin, 
extract_by_obid, 
independent_functionElimination, 
Error :productIsType, 
Error :functionIsType, 
independent_pairEquality, 
Error :lambdaEquality_alt, 
dependent_functionElimination, 
axiomEquality, 
Error :functionIsTypeImplies, 
Error :inhabitedIsType, 
instantiate, 
isectElimination, 
universeEquality
Latex:
\mforall{}[T:Type].  EquivRel(Base;x,y.(x  \mmember{}  T  \mLeftarrow{}{}\mRightarrow{}  y  \mmember{}  T)  \mwedge{}  ((x  \mmember{}  T)  {}\mRightarrow{}  (x  =  y)))
Date html generated:
2019_06_20-PM-00_33_20
Last ObjectModification:
2018_11_25-PM-06_36_28
Theory : quot_1
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