Nuprl Lemma : qavg-between
∀[a,b:ℚ].  a < qavg(a;b) < b supposing a < b
Proof
Definitions occuring in Statement : 
qavg: qavg(a;b), 
q-between: a < b < c, 
qless: r < s, 
rationals: ℚ, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x]
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
qavg: qavg(a;b), 
q-between: a < b < c, 
and: P ∧ Q, 
implies: P ⇒ Q, 
prop: ℙ, 
subtype_rel: A ⊆r B, 
qless: r < s, 
grp_lt: a < b, 
set_lt: a <p b, 
assert: ↑b, 
ifthenelse: if b then t else f fi , 
set_blt: a <b b, 
band: p ∧b q, 
infix_ap: x f y, 
set_le: ≤b, 
pi2: snd(t), 
oset_of_ocmon: g↓oset, 
dset_of_mon: g↓set, 
grp_le: ≤b, 
pi1: fst(t), 
qadd_grp: <ℚ+>, 
q_le: q_le(r;s), 
callbyvalueall: callbyvalueall, 
evalall: evalall(t), 
bor: p ∨bq, 
qpositive: qpositive(r), 
qsub: r - s, 
qadd: r + s, 
qmul: r * s, 
btrue: tt, 
lt_int: i <z j, 
bnot: ¬bb, 
bfalse: ff, 
qeq: qeq(r;s), 
eq_int: (i =z j), 
true: True, 
uiff: uiff(P;Q), 
cand: A c∧ B, 
rev_uimplies: rev_uimplies(P;Q), 
squash: ↓T, 
not: ¬A, 
false: False, 
guard: {T}, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q
Lemmas referenced : 
qadd_comm_q, 
q_distrib, 
qmul_ident, 
qadd_preserves_qless, 
iff_weakening_equal, 
equal_wf, 
assert-qeq, 
qmul-qdiv-cancel, 
true_wf, 
squash_wf, 
qadd_wf, 
qdiv_wf, 
qmul_wf, 
int-subtype-rationals, 
qmul_preserves_qless, 
rationals_wf, 
qless_wf, 
qavg_wf, 
qless_witness
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalRule, 
sqequalHypSubstitution, 
productElimination, 
thin, 
independent_pairEquality, 
lemma_by_obid, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
independent_functionElimination, 
because_Cache, 
isect_memberEquality, 
equalityTransitivity, 
equalitySymmetry, 
natural_numberEquality, 
applyEquality, 
independent_isectElimination, 
independent_pairFormation, 
lambdaEquality, 
imageElimination, 
lambdaFormation, 
voidElimination, 
imageMemberEquality, 
baseClosed, 
universeEquality
Latex:
\mforall{}[a,b:\mBbbQ{}].    a  <  qavg(a;b)  <  b  supposing  a  <  b
Date html generated:
2016_05_15-PM-11_06_06
Last ObjectModification:
2016_01_16-PM-09_28_21
Theory : rationals
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