Nuprl Lemma : dense-in-interval-implies
∀I:Interval
  ∀[X:{a:ℝ| a ∈ I}  ⟶ ℙ]
    (dense-in-interval(I;X)
    ⇒ (∃u,v:{a:ℝ| a ∈ I} . u ≠ v)
    ⇒ (∀a:{a:ℝ| a ∈ I} . ∃x:ℕ ⟶ {a:ℝ| a ∈ I} . ((∀n:ℕ. (X (x n))) ∧ lim n→∞.x n = a)))
Proof
Definitions occuring in Statement : 
dense-in-interval: dense-in-interval(I;X), 
i-member: r ∈ I, 
interval: Interval, 
converges-to: lim n→∞.x[n] = y, 
rneq: x ≠ y, 
real: ℝ, 
nat: ℕ, 
uall: ∀[x:A]. B[x], 
prop: ℙ, 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q, 
set: {x:A| B[x]} , 
apply: f a, 
function: x:A ⟶ B[x]
Definitions unfolded in proof : 
so_apply: x[s], 
so_lambda: λ2x.t[x], 
subtype_rel: A ⊆r B, 
cand: A c∧ B, 
uimplies: b supposing a, 
guard: {T}, 
squash: ↓T, 
sq_stable: SqStable(P), 
and: P ∧ Q, 
dense-in-interval: dense-in-interval(I;X), 
rneq: x ≠ y, 
prop: ℙ, 
or: P ∨ Q, 
member: t ∈ T, 
exists: ∃x:A. B[x], 
implies: P ⇒ Q, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
true: True, 
less_than': less_than'(a;b), 
less_than: a < b, 
rev_implies: P ⇐ Q, 
iff: P ⇐⇒ Q, 
rev_uimplies: rev_uimplies(P;Q), 
uiff: uiff(P;Q), 
top: Top, 
not: ¬A, 
false: False, 
req_int_terms: t1 ≡ t2, 
rge: x ≥ y, 
pi1: fst(t), 
nat: ℕ, 
nequal: a ≠ b ∈ T , 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
decidable: Dec(P), 
assert: ↑b, 
bnot: ¬bb, 
sq_type: SQType(T), 
bfalse: ff, 
it: ⋅, 
unit: Unit, 
bool: 𝔹, 
btrue: tt, 
ifthenelse: if b then t else f fi , 
subtract: n - m, 
eq_int: (i =z j), 
primrec: primrec(n;b;c), 
exp: i^n, 
nat_plus: ℕ+, 
le: A ≤ B, 
rnonneg: rnonneg(x), 
rleq: x ≤ y, 
ge: i ≥ j , 
rdiv: (x/y), 
int_nzero: ℤ-o
Lemmas referenced : 
interval_wf, 
dense-in-interval_wf, 
exists_wf, 
set_wf, 
real_wf, 
rless_wf, 
i-member_wf, 
rleq_weakening_rless, 
sq_stable__i-member, 
i-member-between, 
rneq_wf, 
rneq-cases, 
rless-int, 
int-to-real_wf, 
rdiv_wf, 
rmul_wf, 
rsub_wf, 
rabs_wf, 
rleq_wf, 
ravg_wf, 
ravg-between, 
sq_stable_rneq, 
ravg_comm, 
rsub_functionality, 
rabs_functionality, 
req_inversion, 
req_weakening, 
rleq_functionality, 
ravg-dist, 
real_term_value_var_lemma, 
real_term_value_const_lemma, 
real_term_value_sub_lemma, 
real_polynomial_null, 
rabs-of-nonneg, 
rabs-difference-symmetry, 
req-iff-rsub-is-0, 
itermVar_wf, 
itermConstant_wf, 
itermSubtract_wf, 
rleq_weakening, 
rsub_functionality_wrt_rleq, 
rleq_weakening_equal, 
rleq_functionality_wrt_implies, 
real_term_value_add_lemma, 
itermAdd_wf, 
radd-zero, 
radd_wf, 
radd-preserves-rleq, 
subtype_rel_sets, 
all_wf, 
equal_wf, 
converges-to_wf, 
nat_wf, 
int_seg_wf, 
primrec_wf, 
primrec-wf2, 
less_than_wf, 
le_wf, 
int_formula_prop_wf, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_term_value_subtract_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_and_lemma, 
intformless_wf, 
intformle_wf, 
intformnot_wf, 
intformand_wf, 
full-omega-unsat, 
decidable__le, 
subtract_wf, 
neg_assert_of_eq_int, 
assert-bnot, 
bool_subtype_base, 
subtype_base_sq, 
bool_cases_sqequal, 
eqff_to_assert, 
assert_of_eq_int, 
eqtt_to_assert, 
bool_wf, 
eq_int_wf, 
primrec-unroll, 
exp-positive, 
exp0_lemma, 
nat_plus_wf, 
nat_plus_properties, 
exp_wf2, 
less_than'_wf, 
ge_wf, 
nat_properties, 
real_term_value_mul_lemma, 
real_term_value_minus_lemma, 
rmul-identity1, 
rinv1, 
rmul_functionality, 
req_transitivity, 
itermMultiply_wf, 
rinv_wf2, 
itermMinus_wf, 
rminus_wf, 
int_formula_prop_eq_lemma, 
intformeq_wf, 
nequal_wf, 
true_wf, 
exp_wf3, 
int_nzero-rational, 
int-subtype-rationals, 
equal_functionality_wrt_subtype_rel2, 
int_subtype_base, 
rationals_wf, 
equal-wf-base, 
not_functionality_wrt_implies, 
rneq-int, 
rinv-mul-as-rdiv, 
rmul-rinv3, 
rmul_preserves_rleq, 
exp_wf_nat_plus, 
req-int-fractions, 
one-mul, 
exp_step, 
exp-positive-stronger, 
rmul_assoc, 
simple-converges-to
Rules used in proof : 
cumulativity, 
functionEquality, 
inrFormation, 
universeEquality, 
lambdaEquality, 
setEquality, 
functionExtensionality, 
applyEquality, 
productEquality, 
inlFormation, 
independent_pairFormation, 
dependent_set_memberEquality, 
independent_isectElimination, 
imageElimination, 
baseClosed, 
imageMemberEquality, 
sqequalRule, 
isectElimination, 
dependent_pairFormation, 
unionElimination, 
hypothesisEquality, 
independent_functionElimination, 
hypothesis, 
because_Cache, 
rename, 
setElimination, 
dependent_functionElimination, 
extract_by_obid, 
introduction, 
thin, 
productElimination, 
sqequalHypSubstitution, 
cut, 
isect_memberFormation, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
natural_numberEquality, 
voidEquality, 
voidElimination, 
isect_memberEquality, 
intEquality, 
int_eqEquality, 
approximateComputation, 
equalitySymmetry, 
equalityTransitivity, 
promote_hyp, 
instantiate, 
equalityElimination, 
axiomEquality, 
minusEquality, 
independent_pairEquality, 
intWeakElimination, 
addLevel, 
closedConclusion, 
baseApply
Latex:
\mforall{}I:Interval
    \mforall{}[X:\{a:\mBbbR{}|  a  \mmember{}  I\}    {}\mrightarrow{}  \mBbbP{}]
        (dense-in-interval(I;X)
        {}\mRightarrow{}  (\mexists{}u,v:\{a:\mBbbR{}|  a  \mmember{}  I\}  .  u  \mneq{}  v)
        {}\mRightarrow{}  (\mforall{}a:\{a:\mBbbR{}|  a  \mmember{}  I\}  .  \mexists{}x:\mBbbN{}  {}\mrightarrow{}  \{a:\mBbbR{}|  a  \mmember{}  I\}  .  ((\mforall{}n:\mBbbN{}.  (X  (x  n)))  \mwedge{}  lim  n\mrightarrow{}\minfty{}.x  n  =  a)))
 Date html generated: 
2017_10_03-AM-10_19_34
 Last ObjectModification: 
2017_07_31-AM-11_30_20
Theory : reals
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