Nuprl Lemma : int?_wf
∀[T:Type]. ∀[x:T]. (int?(x) ∈ {y:ℤ| y ~ x}  + T) supposing value-type(T) ∧ (T ⊆r Base)
Proof
Definitions occuring in Statement : 
int?: int?(x)
, 
value-type: value-type(T)
, 
uimplies: b supposing a
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
and: P ∧ Q
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
union: left + right
, 
int: ℤ
, 
base: Base
, 
universe: Type
, 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
int?: int?(x)
, 
and: P ∧ Q
, 
has-value: (a)↓
, 
subtype_rel: A ⊆r B
, 
top: Top
Lemmas referenced : 
value-type-has-value, 
has-value_wf_base, 
is-exception_wf, 
istype-sqequal, 
int_subtype_base, 
istype-top, 
istype-void, 
istype-int, 
value-type_wf, 
subtype_rel_wf, 
base_wf, 
istype-universe
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
sqequalRule, 
sqequalHypSubstitution, 
productElimination, 
thin, 
callbyvalueReduce, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
independent_isectElimination, 
hypothesis, 
isintCases, 
divergentSqle, 
because_Cache, 
baseClosed, 
applyEquality, 
isintReduceTrue, 
equalityTransitivity, 
equalitySymmetry, 
Error :inlEquality_alt, 
Error :dependent_set_memberEquality_alt, 
Error :inhabitedIsType, 
axiomSqEquality, 
Error :isect_memberEquality_alt, 
Error :isectIsTypeImplies, 
voidElimination, 
Error :inrEquality_alt, 
Error :setIsType, 
baseApply, 
closedConclusion, 
axiomEquality, 
Error :universeIsType, 
Error :productIsType, 
instantiate, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[x:T].  (int?(x)  \mmember{}  \{y:\mBbbZ{}|  y  \msim{}  x\}    +  T)  supposing  value-type(T)  \mwedge{}  (T  \msubseteq{}r  Base)
Date html generated:
2019_06_20-AM-11_33_10
Last ObjectModification:
2019_02_07-PM-00_06_32
Theory : int_1
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