Nuprl Lemma : ravg-dist-when-rleq
∀[x,y:ℝ].  ((ravg(x;y) - x) = ((r1/r(2)) * (y - x))) ∧ ((y - ravg(x;y)) = ((r1/r(2)) * (y - x))) supposing x ≤ y
Proof
Definitions occuring in Statement : 
ravg: ravg(x;y), 
rdiv: (x/y), 
rleq: x ≤ y, 
rsub: x - y, 
req: x = y, 
rmul: a * b, 
int-to-real: r(n), 
real: ℝ, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
and: P ∧ Q, 
natural_number: $n
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
and: P ∧ Q, 
cand: A c∧ B, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
rneq: x ≠ y, 
guard: {T}, 
or: P ∨ Q, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
less_than: a < b, 
squash: ↓T, 
less_than': less_than'(a;b), 
true: True, 
prop: ℙ, 
uiff: uiff(P;Q), 
req_int_terms: t1 ≡ t2, 
false: False, 
not: ¬A, 
top: Top
Lemmas referenced : 
ravg-dist, 
ravg-weak-between, 
req_witness, 
rsub_wf, 
ravg_wf, 
rmul_wf, 
rdiv_wf, 
int-to-real_wf, 
rless-int, 
rless_wf, 
rleq_wf, 
real_wf, 
rabs_wf, 
rleq-implies-rleq, 
itermSubtract_wf, 
itermVar_wf, 
itermConstant_wf, 
req-iff-rsub-is-0, 
req_functionality, 
rabs-of-nonneg, 
rmul_functionality, 
req_weakening, 
real_polynomial_null, 
istype-int, 
real_term_value_sub_lemma, 
istype-void, 
real_term_value_var_lemma, 
real_term_value_const_lemma, 
rabs-difference-symmetry
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
productElimination, 
because_Cache, 
independent_functionElimination, 
hypothesis, 
independent_pairFormation, 
sqequalRule, 
independent_pairEquality, 
isectElimination, 
closedConclusion, 
natural_numberEquality, 
independent_isectElimination, 
inrFormation_alt, 
imageMemberEquality, 
baseClosed, 
universeIsType, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
inhabitedIsType, 
approximateComputation, 
lambdaEquality_alt, 
int_eqEquality, 
voidElimination
Latex:
\mforall{}[x,y:\mBbbR{}].
    ((ravg(x;y)  -  x)  =  ((r1/r(2))  *  (y  -  x)))  \mwedge{}  ((y  -  ravg(x;y))  =  ((r1/r(2))  *  (y  -  x)))  
    supposing  x  \mleq{}  y
 Date html generated: 
2019_10_29-AM-10_03_39
 Last ObjectModification: 
2019_01_11-AM-11_10_53
Theory : reals
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