Nuprl Lemma : metric-strong-extensionality
∀[X:Type]
  ∀d:metric(X)
    (mcomplete(X with d)
    
⇒ (∀Y:Type. ∀d':metric(Y). ∀f:X ⟶ Y.
          ((∀x1,x2:X.  (x1 ≡ x2 
⇒ f[x1] ≡ f[x2])) 
⇒ (∀x1,x2:X.  (f[x1] # f[x2] 
⇒ x1 # x2)))))
Proof
Definitions occuring in Statement : 
mcomplete: mcomplete(M)
, 
mk-metric-space: X with d
, 
msep: x # y
, 
meq: x ≡ y
, 
metric: metric(X)
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
so_apply: x[s]
, 
prop: ℙ
, 
or: P ∨ Q
, 
not: ¬A
, 
false: False
, 
msep: x # y
, 
meq: x ≡ y
, 
mdist: mdist(d;x;y)
, 
guard: {T}
, 
uimplies: b supposing a
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
Lemmas referenced : 
metric-weak-Markov, 
msep_wf, 
meq_wf, 
metric_wf, 
mcomplete_wf, 
mk-metric-space_wf, 
istype-universe, 
msep-or, 
istype-void, 
rless_transitivity1, 
int-to-real_wf, 
mdist_wf, 
rleq_weakening, 
rless_irreflexivity, 
req_functionality, 
mdist-symm, 
req_weakening
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
lambdaFormation_alt, 
dependent_functionElimination, 
independent_functionElimination, 
because_Cache, 
universeIsType, 
applyEquality, 
inhabitedIsType, 
sqequalRule, 
functionIsType, 
instantiate, 
universeEquality, 
unionElimination, 
inlFormation_alt, 
inrFormation_alt, 
natural_numberEquality, 
independent_isectElimination, 
voidElimination, 
productElimination
Latex:
\mforall{}[X:Type]
    \mforall{}d:metric(X)
        (mcomplete(X  with  d)
        {}\mRightarrow{}  (\mforall{}Y:Type.  \mforall{}d':metric(Y).  \mforall{}f:X  {}\mrightarrow{}  Y.
                    ((\mforall{}x1,x2:X.    (x1  \mequiv{}  x2  {}\mRightarrow{}  f[x1]  \mequiv{}  f[x2]))  {}\mRightarrow{}  (\mforall{}x1,x2:X.    (f[x1]  \#  f[x2]  {}\mRightarrow{}  x1  \#  x2)))))
Date html generated:
2019_10_30-AM-06_47_36
Last ObjectModification:
2019_10_02-AM-10_58_39
Theory : reals
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