Nuprl Lemma : stable-union-metric-subspace
∀[X:Type]. ∀[d:metric(X)]. ∀[T:Type]. ∀[P:T ⟶ X ⟶ ℙ].
  metric-subspace(X;d;stable-union(X;T;i,x.P[i;x])) supposing ∀i:T. ∀x,y:X.  (P[i;x] 
⇒ y ≡ x 
⇒ P[i;y])
Proof
Definitions occuring in Statement : 
metric-subspace: metric-subspace(X;d;A)
, 
meq: x ≡ y
, 
metric: metric(X)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s1;s2]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
guard: {T}
, 
false: False
, 
not: ¬A
, 
subtype_rel: A ⊆r B
, 
so_lambda: λ2x y.t[x; y]
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
so_apply: x[s]
, 
so_apply: x[s1;s2]
, 
exists: ∃x:A. B[x]
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
stable-union: Error :stable-union, 
and: P ∧ Q
, 
metric-subspace: metric-subspace(X;d;A)
, 
uimplies: b supposing a
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
istype-void, 
istype-universe, 
metric_wf, 
subtype_rel_self, 
strong-subtype_witness, 
Error :stable-union_wf, 
meq_wf, 
strong-subtype-self, 
not_wf, 
strong-subtype-set3
Rules used in proof : 
voidElimination, 
productIsType, 
dependent_pairFormation_alt, 
promote_hyp, 
dependent_set_memberEquality_alt, 
isectIsTypeImplies, 
isect_memberEquality_alt, 
universeEquality, 
instantiate, 
functionIsType, 
functionIsTypeImplies, 
equalitySymmetry, 
equalityTransitivity, 
axiomEquality, 
dependent_functionElimination, 
independent_functionElimination, 
independent_pairEquality, 
productElimination, 
inhabitedIsType, 
rename, 
setElimination, 
lambdaFormation_alt, 
independent_isectElimination, 
universeIsType, 
hypothesis, 
applyEquality, 
productEquality, 
lambdaEquality_alt, 
sqequalRule, 
because_Cache, 
hypothesisEquality, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
independent_pairFormation, 
cut, 
introduction, 
isect_memberFormation_alt, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}[X:Type].  \mforall{}[d:metric(X)].  \mforall{}[T:Type].  \mforall{}[P:T  {}\mrightarrow{}  X  {}\mrightarrow{}  \mBbbP{}].
    metric-subspace(X;d;stable-union(X;T;i,x.P[i;x])) 
    supposing  \mforall{}i:T.  \mforall{}x,y:X.    (P[i;x]  {}\mRightarrow{}  y  \mequiv{}  x  {}\mRightarrow{}  P[i;y])
Date html generated:
2019_10_30-AM-06_31_28
Last ObjectModification:
2019_10_24-AM-10_23_16
Theory : reals
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