Nuprl Lemma : Russell-theorem
¬(Type ∈ Type)
Proof
Definitions occuring in Statement : 
not: ¬A
, 
member: t ∈ T
, 
universe: Type
Definitions unfolded in proof : 
not: ¬A
, 
implies: P 
⇒ Q
, 
false: False
, 
member: t ∈ T
, 
Russell: Russell
, 
isect2: T1 ⋂ T2
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
uall: ∀[x:A]. B[x]
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
prop: ℙ
Lemmas referenced : 
Russell-property, 
istype-universe, 
isect2_subtype_rel, 
base_wf, 
isect2_subtype_rel2, 
istype-void, 
isect2_wf, 
not_wf, 
equal-wf-base
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
hypothesis, 
sqequalHypSubstitution, 
independent_functionElimination, 
thin, 
voidElimination, 
sqequalRule, 
equalityIsType4, 
universeIsType, 
universeEquality, 
baseClosed, 
because_Cache, 
dependent_set_memberEquality_alt, 
isect_memberEquality, 
unionElimination, 
equalityElimination, 
functionIsType, 
isectElimination, 
hypothesisEquality, 
applyEquality, 
instantiate, 
cumulativity, 
equalityTransitivity, 
equalitySymmetry, 
setEquality
Latex:
\mneg{}(Type  \mmember{}  Type)
Date html generated:
2019_10_15-AM-10_46_48
Last ObjectModification:
2018_10_09-AM-09_54_22
Theory : basic
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