Nuprl Lemma : image-metric_wf
∀[X,Y:Type]. ∀[f:X ⟶ Y]. ∀[d:metric(Y)].  (image-metric(d) ∈ metric(f[X]))
Proof
Definitions occuring in Statement : 
image-metric: image-metric(d), 
image-space: f[X], 
metric: metric(X), 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
function: x:A ⟶ B[x], 
universe: Type
Definitions unfolded in proof : 
prop: ℙ, 
mdist: mdist(d;x;y), 
pi1: fst(t), 
all: ∀x:A. B[x], 
cand: A c∧ B, 
and: P ∧ Q, 
top: Top, 
image-space: f[X], 
metric: metric(X), 
image-metric: image-metric(d), 
member: t ∈ T, 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
istype-universe, 
metric_wf, 
int-to-real_wf, 
req_wf, 
radd_wf, 
rleq_wf, 
mdist-same, 
mdist-triangle-inequality1, 
image-space_wf, 
istype-void, 
pi1_wf_top
Rules used in proof : 
universeEquality, 
instantiate, 
isectIsTypeImplies, 
axiomEquality, 
natural_numberEquality, 
functionIsType, 
productIsType, 
because_Cache, 
equalityElimination, 
independent_pairFormation, 
lambdaFormation_alt, 
equalitySymmetry, 
equalityTransitivity, 
dependent_set_memberEquality_alt, 
universeIsType, 
inhabitedIsType, 
voidElimination, 
isect_memberEquality_alt, 
independent_pairEquality, 
productElimination, 
isectElimination, 
extract_by_obid, 
hypothesis, 
hypothesisEquality, 
rename, 
thin, 
setElimination, 
sqequalHypSubstitution, 
applyEquality, 
lambdaEquality_alt, 
sqequalRule, 
cut, 
introduction, 
isect_memberFormation_alt, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}[X,Y:Type].  \mforall{}[f:X  {}\mrightarrow{}  Y].  \mforall{}[d:metric(Y)].    (image-metric(d)  \mmember{}  metric(f[X]))
Date html generated:
2019_10_30-AM-06_35_27
Last ObjectModification:
2019_10_25-AM-11_11_40
Theory : reals
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