Nuprl Lemma : rmin3-rmax3-subinterval
∀I:Interval. ∀a,b,c:ℝ.  ((a ∈ I) 
⇒ (b ∈ I) 
⇒ (c ∈ I) 
⇒ [rmin(a;rmin(b;c)), rmax(a;rmax(b;c))] ⊆ I )
Proof
Definitions occuring in Statement : 
subinterval: I ⊆ J 
, 
rccint: [l, u]
, 
i-member: r ∈ I
, 
interval: Interval
, 
rmin: rmin(x;y)
, 
rmax: rmax(x;y)
, 
real: ℝ
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
cand: A c∧ B
, 
prop: ℙ
Lemmas referenced : 
rcc-subinterval, 
rmin_wf, 
rmax_wf, 
rmin-i-member, 
rmax-i-member, 
rleq_wf, 
i-member_wf, 
real_wf, 
interval_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
isectElimination, 
hypothesis, 
productElimination, 
independent_functionElimination, 
because_Cache, 
independent_pairFormation
Latex:
\mforall{}I:Interval.  \mforall{}a,b,c:\mBbbR{}.
    ((a  \mmember{}  I)  {}\mRightarrow{}  (b  \mmember{}  I)  {}\mRightarrow{}  (c  \mmember{}  I)  {}\mRightarrow{}  [rmin(a;rmin(b;c)),  rmax(a;rmax(b;c))]  \msubseteq{}  I  )
Date html generated:
2016_10_26-AM-09_31_28
Last ObjectModification:
2016_08_23-PM-01_15_19
Theory : reals
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