Nuprl Lemma : qavg-qle-iff-2
∀[a,b:ℚ].  uiff(qavg(b;a) ≤ b;a ≤ b)
Proof
Definitions occuring in Statement : 
qavg: qavg(a;b), 
qle: r ≤ s, 
rationals: ℚ, 
uiff: uiff(P;Q), 
uall: ∀[x:A]. B[x]
Definitions unfolded in proof : 
rev_implies: P ⇐ Q, 
rev_uimplies: rev_uimplies(P;Q), 
bnot: ¬bb, 
dset_of_mon: g↓set, 
oset_of_ocmon: g↓oset, 
set_le: ≤b, 
band: p ∧b q, 
set_blt: a <b b, 
set_lt: a <p b, 
grp_lt: a < b, 
qless: r < s, 
iff: P ⇐⇒ Q, 
squash: ↓T, 
guard: {T}, 
true: True, 
lt_int: i <z j, 
qmul: r * s, 
qadd: r + s, 
qsub: r - s, 
qpositive: qpositive(r), 
bor: p ∨bq, 
q_le: q_le(r;s), 
qadd_grp: <ℚ+>, 
pi2: snd(t), 
pi1: fst(t), 
grp_le: ≤b, 
infix_ap: x f y, 
grp_leq: a ≤ b, 
qle: r ≤ s, 
prop: ℙ, 
false: False, 
assert: ↑b, 
bfalse: ff, 
eq_int: (i =z j), 
btrue: tt, 
ifthenelse: if b then t else f fi , 
evalall: evalall(t), 
callbyvalueall: callbyvalueall, 
qeq: qeq(r;s), 
not: ¬A, 
subtype_rel: A ⊆r B, 
implies: P ⇒ Q, 
uimplies: b supposing a, 
and: P ∧ Q, 
uiff: uiff(P;Q), 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
qavg: qavg(a;b)
Lemmas referenced : 
qmul_preserves_qle, 
iff_weakening_equal, 
qmul-qdiv-cancel, 
subtype_rel_self, 
equal-wf-T-base, 
not_wf, 
true_wf, 
squash_wf, 
qmul_one_qrng, 
q_distrib, 
mon_ident_q, 
qinverse_q, 
qadd_comm_q, 
qadd_ac_1_q, 
qadd_preserves_qle, 
uiff_transitivity2, 
int-subtype-rationals, 
qmul_wf, 
qmul_preserves_qle2, 
rationals_wf, 
assert-qeq, 
qadd_wf, 
qdiv_wf, 
qle_wf, 
qle_witness
Rules used in proof : 
universeEquality, 
instantiate, 
imageMemberEquality, 
imageElimination, 
lambdaEquality_alt, 
minusEquality, 
isectIsTypeImplies, 
isect_memberEquality_alt, 
independent_pairEquality, 
sqequalBase, 
baseClosed, 
inhabitedIsType, 
equalityIstype, 
voidElimination, 
productElimination, 
equalitySymmetry, 
equalityTransitivity, 
lambdaFormation_alt, 
independent_isectElimination, 
because_Cache, 
applyEquality, 
natural_numberEquality, 
universeIsType, 
hypothesis, 
independent_functionElimination, 
hypothesisEquality, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
independent_pairFormation, 
cut, 
introduction, 
isect_memberFormation_alt, 
computationStep, 
sqequalTransitivity, 
sqequalReflexivity, 
sqequalRule, 
sqequalSubstitution
Latex:
\mforall{}[a,b:\mBbbQ{}].    uiff(qavg(b;a)  \mleq{}  b;a  \mleq{}  b)
Date html generated:
2019_10_29-AM-07_46_03
Last ObjectModification:
2019_10_21-PM-08_23_31
Theory : rationals
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