Nuprl Lemma : qmax-list-bounds
∀L:ℚ List
  (0 < ||L||
  ⇒ (∀x:ℚ
        ((qmax-list(L) ≤ x ⇐⇒ (∀y∈L.y ≤ x))
        ∧ (x ≤ qmax-list(L) ⇐⇒ (∃y∈L. x ≤ y))
        ∧ (qmax-list(L) < x ⇐⇒ (∀y∈L.y < x))
        ∧ (x < qmax-list(L) ⇐⇒ (∃y∈L. x < y)))))
Proof
Definitions occuring in Statement : 
qmax-list: qmax-list(L), 
qle: r ≤ s, 
qless: r < s, 
rationals: ℚ, 
l_exists: (∃x∈L. P[x]), 
l_all: (∀x∈L.P[x]), 
length: ||as||, 
list: T List, 
less_than: a < b, 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
implies: P ⇒ Q, 
and: P ∧ Q, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q, 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
so_lambda: λ2x y.t[x; y], 
so_apply: x[s1;s2], 
uimplies: b supposing a, 
qmax-list: qmax-list(L), 
iff: P ⇐⇒ Q, 
prop: ℙ, 
rev_implies: P ⇐ Q, 
qmax: qmax(x;y), 
guard: {T}, 
not: ¬A, 
false: False, 
uiff: uiff(P;Q), 
or: P ∨ Q, 
sq_type: SQType(T), 
ifthenelse: if b then t else f fi , 
btrue: tt, 
bfalse: ff, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
cand: A c∧ B, 
assoc: Assoc(T;op), 
infix_ap: x f y
Lemmas referenced : 
rationals_wf, 
istype-less_than, 
length_wf, 
list_wf, 
combine-list-rel-and, 
qmax_wf, 
qle_wf, 
q_le_wf, 
qle_transitivity_qorder, 
assert_wf, 
bnot_wf, 
not_wf, 
istype-assert, 
istype-void, 
qle_complement_qorder, 
bool_cases, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
eqtt_to_assert, 
assert-q_le-eq, 
iff_weakening_equal, 
eqff_to_assert, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bnot, 
qless_transitivity_2_qorder, 
qle_weakening_lt_qorder, 
uiff_transitivity2, 
equal-wf-T-base, 
qmax-assoc, 
combine-list-rel-or, 
qless_transitivity_1_qorder, 
qless_wf, 
qless_transitivity
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
independent_pairFormation, 
universeIsType, 
cut, 
introduction, 
extract_by_obid, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
natural_numberEquality, 
hypothesisEquality, 
dependent_functionElimination, 
sqequalRule, 
lambdaEquality_alt, 
inhabitedIsType, 
independent_functionElimination, 
independent_isectElimination, 
productElimination, 
productIsType, 
because_Cache, 
equalityTransitivity, 
equalitySymmetry, 
functionIsType, 
unionElimination, 
instantiate, 
cumulativity, 
equalityElimination, 
baseClosed, 
voidElimination, 
equalityIstype, 
isect_memberFormation_alt, 
isect_memberEquality_alt, 
axiomEquality, 
isectIsTypeImplies, 
unionIsType, 
inrFormation_alt, 
inlFormation_alt
Latex:
\mforall{}L:\mBbbQ{}  List
    (0  <  ||L||
    {}\mRightarrow{}  (\mforall{}x:\mBbbQ{}
                ((qmax-list(L)  \mleq{}  x  \mLeftarrow{}{}\mRightarrow{}  (\mforall{}y\mmember{}L.y  \mleq{}  x))
                \mwedge{}  (x  \mleq{}  qmax-list(L)  \mLeftarrow{}{}\mRightarrow{}  (\mexists{}y\mmember{}L.  x  \mleq{}  y))
                \mwedge{}  (qmax-list(L)  <  x  \mLeftarrow{}{}\mRightarrow{}  (\mforall{}y\mmember{}L.y  <  x))
                \mwedge{}  (x  <  qmax-list(L)  \mLeftarrow{}{}\mRightarrow{}  (\mexists{}y\mmember{}L.  x  <  y)))))
Date html generated:
2020_05_20-AM-09_16_12
Last ObjectModification:
2020_01_10-PM-04_21_30
Theory : rationals
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