Nuprl Lemma : ifun-alt
∀I:Interval. ∀[f:I ⟶ℝ]. (ifun(f;I)) supposing ((∀x,y:{x:ℝ| x ∈ I} .  ((x = y) 
⇒ ((f x) = (f y)))) and icompact(I))
Proof
Definitions occuring in Statement : 
ifun: ifun(f;I)
, 
icompact: icompact(I)
, 
rfun: I ⟶ℝ
, 
i-member: r ∈ I
, 
interval: Interval
, 
req: x = y
, 
real: ℝ
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
set: {x:A| B[x]} 
, 
apply: f a
Definitions unfolded in proof : 
guard: {T}
, 
cand: A c∧ B
, 
top: Top
, 
subinterval: I ⊆ J 
, 
and: P ∧ Q
, 
icompact: icompact(I)
, 
squash: ↓T
, 
sq_stable: SqStable(P)
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
prop: ℙ
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
real-fun: real-fun(f;a;b)
, 
ifun: ifun(f;I)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
r-ap: f(x)
Lemmas referenced : 
sq_stable__req, 
sq_stable__rleq, 
member_rccint_lemma, 
trivial-subinterval, 
sq_stable__icompact, 
interval_wf, 
rfun_wf, 
icompact_wf, 
sq_stable__i-member, 
r-ap_wf, 
all_wf, 
right-endpoint_wf, 
left-endpoint_wf, 
rccint_wf, 
i-member_wf, 
real_wf, 
set_wf, 
req_wf
Rules used in proof : 
dependent_set_memberEquality, 
independent_pairFormation, 
voidEquality, 
voidElimination, 
isect_memberEquality, 
productElimination, 
imageElimination, 
baseClosed, 
imageMemberEquality, 
independent_functionElimination, 
dependent_functionElimination, 
functionEquality, 
setEquality, 
independent_isectElimination, 
lambdaEquality, 
because_Cache, 
hypothesis, 
hypothesisEquality, 
rename, 
setElimination, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
isect_memberFormation, 
lambdaFormation, 
computationStep, 
sqequalTransitivity, 
sqequalReflexivity, 
sqequalRule, 
sqequalSubstitution
Latex:
\mforall{}I:Interval
    \mforall{}[f:I  {}\mrightarrow{}\mBbbR{}]
        (ifun(f;I))  supposing  ((\mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  I\}  .    ((x  =  y)  {}\mRightarrow{}  ((f  x)  =  (f  y))))  and  icompact(I))
Date html generated:
2018_07_29-AM-09_40_30
Last ObjectModification:
2018_07_02-PM-00_31_17
Theory : reals
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