Nuprl Lemma : square-between-lemma3
∀a:ℕ. ∀b,n:ℕ+.  (∃q:ℚ [((a/b) - (1/n) < q * q ∧ q * q < (a/b) + (1/n) ∧ (0 ≤ q))])
Proof
Definitions occuring in Statement : 
qle: r ≤ s
, 
qless: r < s
, 
qsub: r - s
, 
qdiv: (r/s)
, 
qmul: r * s
, 
qadd: r + s
, 
rationals: ℚ
, 
nat_plus: ℕ+
, 
nat: ℕ
, 
all: ∀x:A. B[x]
, 
sq_exists: ∃x:A [B[x]]
, 
and: P ∧ Q
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
nat: ℕ
, 
nat_plus: ℕ+
, 
subtype_rel: A ⊆r B
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
uimplies: b supposing a
, 
sq_exists: ∃x:A [B[x]]
, 
and: P ∧ Q
, 
sq_type: SQType(T)
, 
implies: P 
⇒ Q
, 
guard: {T}
, 
nequal: a ≠ b ∈ T 
, 
ge: i ≥ j 
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
top: Top
, 
cand: A c∧ B
, 
uiff: uiff(P;Q)
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
squash: ↓T
, 
true: True
, 
iff: P 
⇐⇒ Q
, 
rev_uimplies: rev_uimplies(P;Q)
, 
qsub: r - s
, 
qmul: r * s
, 
callbyvalueall: callbyvalueall, 
evalall: evalall(t)
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
rev_implies: P 
⇐ Q
, 
qge: a ≥ b
Lemmas referenced : 
nat_wf, 
divide_wf, 
mul_bounds_1a, 
nat_plus_subtype_nat, 
le_wf, 
set-value-type, 
equal_wf, 
istype-int, 
int-value-type, 
square-between-lemma2, 
subtype_base_sq, 
set_subtype_base, 
int_subtype_base, 
qless_wf, 
qsub_wf, 
qdiv_wf, 
subtype_rel_set, 
rationals_wf, 
int-subtype-rationals, 
less_than_wf, 
int_nzero-rational, 
nat_plus_inc_int_nzero, 
qmul_wf, 
qadd_wf, 
qle_wf, 
nat_plus_wf, 
div_rem_sum, 
div_bounds_1, 
rem_bounds_1, 
nat_plus_properties, 
nat_properties, 
full-omega-unsat, 
intformand_wf, 
intformeq_wf, 
itermVar_wf, 
itermConstant_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_eq_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
qmul_preserves_qle2, 
qle-int, 
decidable__le, 
intformnot_wf, 
intformle_wf, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
qle_witness, 
squash_wf, 
true_wf, 
qmul-qdiv-cancel, 
subtype_rel_self, 
iff_weakening_equal, 
qmul_preserves_qless, 
qless-int, 
decidable__lt, 
qmul_over_plus_qrng, 
qmul_over_minus_qrng, 
qmul_comm_qrng, 
qadd_comm_q, 
qmul-qdiv-cancel3, 
qless_functionality_wrt_implies_1, 
qle_weakening_eq_qorder, 
qmul_functionality_wrt_qle, 
qmul-mul, 
itermAdd_wf, 
itermMultiply_wf, 
int_term_value_add_lemma, 
int_term_value_mul_lemma, 
qadd-add, 
qless_witness, 
qmul_preserves_qle, 
qmul_one_qrng, 
qless_transitivity_2_qorder
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
dependent_set_memberEquality_alt, 
multiplyEquality, 
setElimination, 
rename, 
hypothesisEquality, 
applyEquality, 
sqequalRule, 
universeIsType, 
natural_numberEquality, 
cutEval, 
equalityTransitivity, 
equalitySymmetry, 
equalityIsType1, 
inhabitedIsType, 
lambdaEquality_alt, 
independent_isectElimination, 
intEquality, 
dependent_functionElimination, 
instantiate, 
cumulativity, 
productElimination, 
because_Cache, 
independent_functionElimination, 
productIsType, 
remainderEquality, 
approximateComputation, 
dependent_pairFormation_alt, 
int_eqEquality, 
isect_memberEquality_alt, 
voidElimination, 
independent_pairFormation, 
equalityIsType4, 
baseApply, 
closedConclusion, 
baseClosed, 
divideEquality, 
addEquality, 
unionElimination, 
isect_memberFormation_alt, 
imageElimination, 
imageMemberEquality, 
universeEquality, 
minusEquality
Latex:
\mforall{}a:\mBbbN{}.  \mforall{}b,n:\mBbbN{}\msupplus{}.    (\mexists{}q:\mBbbQ{}  [((a/b)  -  (1/n)  <  q  *  q  \mwedge{}  q  *  q  <  (a/b)  +  (1/n)  \mwedge{}  (0  \mleq{}  q))])
Date html generated:
2019_10_16-PM-00_38_04
Last ObjectModification:
2018_10_10-AM-11_04_39
Theory : rationals
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