Nuprl Lemma : change-equality-type
∀[A,B:Type].  (respects-equality(A;B) 
⇒ (∀x,y:A.  ((x = y ∈ A) 
⇒ (x ∈ B) 
⇒ (x = y ∈ B))))
Proof
Definitions occuring in Statement : 
respects-equality: respects-equality(S;T)
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
respects-equality: respects-equality(S;T)
Lemmas referenced : 
respects-equality_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
Error :lambdaFormation_alt, 
sqequalRule, 
Error :equalityIstype, 
Error :universeIsType, 
hypothesisEquality, 
cut, 
hypothesis, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
independent_functionElimination, 
because_Cache, 
introduction, 
extract_by_obid, 
isectElimination, 
Error :inhabitedIsType, 
universeEquality, 
pointwiseFunctionalityForEquality, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}[A,B:Type].    (respects-equality(A;B)  {}\mRightarrow{}  (\mforall{}x,y:A.    ((x  =  y)  {}\mRightarrow{}  (x  \mmember{}  B)  {}\mRightarrow{}  (x  =  y))))
Date html generated:
2019_06_20-AM-11_13_51
Last ObjectModification:
2018_11_28-PM-11_36_14
Theory : core_2
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