Nuprl Lemma : qbetween-qdist
∀[a,b,r,s:ℚ].  (qdist(a;b) ≤ (s - r)) supposing (r ≤ b ≤ s and r ≤ a ≤ s)
Proof
Definitions occuring in Statement : 
qbetween: a ≤ b ≤ c, 
qdist: qdist(r;s), 
qle: r ≤ s, 
qsub: r - s, 
rationals: ℚ, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x]
Definitions unfolded in proof : 
qdist: qdist(r;s), 
qbetween: a ≤ b ≤ c, 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
and: P ∧ Q, 
qabs: |r|, 
callbyvalueall: callbyvalueall, 
has-value: (a)↓, 
has-valueall: has-valueall(a), 
implies: P ⇒ Q, 
prop: ℙ, 
true: True, 
subtype_rel: A ⊆r B, 
uiff: uiff(P;Q), 
rev_uimplies: rev_uimplies(P;Q), 
squash: ↓T, 
guard: {T}, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
all: ∀x:A. B[x], 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
not: ¬A, 
qsub: r - s
Lemmas referenced : 
valueall-type-has-valueall, 
rationals_wf, 
rationals-valueall-type, 
qsub_wf, 
evalall-reduce, 
qle_witness, 
qabs_wf, 
qle_wf, 
qpositive_wf, 
bool_wf, 
equal-wf-T-base, 
assert_wf, 
qless_wf, 
int-subtype-rationals, 
qle-normalize, 
bnot_wf, 
not_wf, 
squash_wf, 
true_wf, 
ifthenelse_wf, 
qminus-qsub, 
iff_weakening_equal, 
uiff_transitivity, 
eqtt_to_assert, 
assert-qpositive, 
iff_transitivity, 
iff_weakening_uiff, 
eqff_to_assert, 
assert_of_bnot, 
equal_wf, 
qadd_wf, 
qmul_wf, 
mon_assoc_q, 
qadd_com, 
qadd_assoc, 
qadd-non-neg
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
introduction, 
cut, 
sqequalHypSubstitution, 
productElimination, 
thin, 
extract_by_obid, 
isectElimination, 
hypothesis, 
independent_isectElimination, 
hypothesisEquality, 
callbyvalueReduce, 
because_Cache, 
independent_functionElimination, 
productEquality, 
isect_memberEquality, 
equalityTransitivity, 
equalitySymmetry, 
natural_numberEquality, 
baseClosed, 
applyEquality, 
lambdaEquality, 
imageElimination, 
universeEquality, 
imageMemberEquality, 
lambdaFormation, 
unionElimination, 
equalityElimination, 
independent_pairFormation, 
impliesFunctionality, 
dependent_functionElimination, 
hyp_replacement, 
applyLambdaEquality, 
minusEquality
Latex:
\mforall{}[a,b,r,s:\mBbbQ{}].    (qdist(a;b)  \mleq{}  (s  -  r))  supposing  (r  \mleq{}  b  \mleq{}  s  and  r  \mleq{}  a  \mleq{}  s)
Date html generated:
2018_05_21-PM-11_58_55
Last ObjectModification:
2017_07_26-PM-06_48_24
Theory : rationals
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