Nuprl Lemma : locally-non-constant-via-rational
∀a,b,c:ℝ. ∀f:[a, b] ⟶ℝ.
  (f[x] continuous for x ∈ [a, b] ⇒ locally-non-constant(f;a;b;c) ⇒ locally-non-constant-rational(f;a;b;c))
Proof
Definitions occuring in Statement : 
locally-non-constant-rational: locally-non-constant-rational(f;a;b;c), 
locally-non-constant: locally-non-constant(f;a;b;c), 
continuous: f[x] continuous for x ∈ I, 
rfun: I ⟶ℝ, 
rccint: [l, u], 
real: ℝ, 
so_apply: x[s], 
all: ∀x:A. B[x], 
implies: P ⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
locally-non-constant: locally-non-constant(f;a;b;c), 
locally-non-constant-rational: locally-non-constant-rational(f;a;b;c), 
member: t ∈ T, 
exists: ∃x:A. B[x], 
and: P ∧ Q, 
continuous: f[x] continuous for x ∈ I, 
i-approx: i-approx(I;n), 
rccint: [l, u], 
iff: P ⇐⇒ Q, 
guard: {T}, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
prop: ℙ, 
top: Top, 
rneq: x ≠ y, 
or: P ∨ Q, 
so_lambda: λ2x.t[x], 
label: ...$L... t, 
rfun: I ⟶ℝ, 
so_apply: x[s], 
i-member: r ∈ I, 
itermConstant: "const", 
req_int_terms: t1 ≡ t2, 
false: False, 
not: ¬A, 
uiff: uiff(P;Q), 
nat_plus: ℕ+, 
rev_implies: P ⇐ Q, 
rless: x < y, 
sq_exists: ∃x:{A| B[x]}, 
decidable: Dec(P), 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
sq_stable: SqStable(P), 
rleq: x ≤ y, 
rnonneg: rnonneg(x), 
le: A ≤ B, 
subtype_rel: A ⊆r B, 
squash: ↓T, 
rdiv: (x/y), 
nequal: a ≠ b ∈ T , 
int_nzero: ℤ-o, 
cand: A c∧ B, 
rsub: x - y, 
rgt: x > y, 
rge: x ≥ y, 
rev_uimplies: rev_uimplies(P;Q), 
r-ap: f(x)
Lemmas referenced : 
rccint-icompact, 
rless_transitivity2, 
rless_transitivity1, 
rleq_weakening_rless, 
icompact_wf, 
rccint_wf, 
member_rccint_lemma, 
rleq_wf, 
rless_wf, 
locally-non-constant_wf, 
continuous_wf, 
i-member_wf, 
real_wf, 
rfun_wf, 
small-reciprocal-real-ext, 
rsub_wf, 
r-ap_wf, 
rleq_transitivity, 
rless-implies-rless, 
int-to-real_wf, 
real_term_polynomial, 
itermSubtract_wf, 
itermVar_wf, 
itermConstant_wf, 
real_term_value_const_lemma, 
real_term_value_sub_lemma, 
real_term_value_var_lemma, 
req-iff-rsub-is-0, 
radd-preserves-rless, 
rdiv_wf, 
rless-int, 
nat_plus_properties, 
decidable__lt, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
radd_wf, 
rmul_wf, 
rinv_wf2, 
sq_stable__and, 
all_wf, 
rabs_wf, 
sq_stable__rless, 
sq_stable__all, 
sq_stable__rleq, 
less_than'_wf, 
nat_plus_wf, 
squash_wf, 
rless_functionality, 
itermAdd_wf, 
itermMultiply_wf, 
real_term_value_add_lemma, 
real_term_value_mul_lemma, 
radd_functionality, 
req_weakening, 
rinv-as-rdiv, 
rless-cases, 
exists_wf, 
int_subtype_base, 
equal-wf-base, 
int_formula_prop_eq_lemma, 
intformeq_wf, 
nequal_wf, 
less_than_wf, 
subtype_rel_sets, 
int-rdiv_wf, 
rmin_wf, 
rationals-dense-ext, 
radd-assoc, 
req_inversion, 
rmin_functionality, 
rminus_functionality, 
radd_comm, 
radd-ac, 
radd-rminus-assoc, 
radd-rminus-both, 
req_transitivity, 
radd-zero-both, 
rminus_wf, 
rmul-distrib2, 
rmul-identity1, 
rminus-as-rmul, 
radd-int, 
rmul_functionality, 
rmul-zero-both, 
rmin_strict_ub, 
rleq_weakening_equal, 
rleq_functionality_wrt_implies, 
int-rdiv-req, 
rleq_functionality, 
uiff_transitivity, 
radd-preserves-rleq, 
rmin-rleq, 
rsub_functionality, 
rabs_functionality, 
rabs-difference-bound-rleq, 
trivial-rsub-rleq, 
radd_functionality_wrt_rless2, 
rleq_weakening, 
radd_functionality_wrt_rleq, 
radd_functionality_wrt_rless1, 
rneq_wf, 
equal_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
sqequalHypSubstitution, 
cut, 
hypothesis, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
productElimination, 
sqequalRule, 
dependent_set_memberEquality, 
because_Cache, 
introduction, 
extract_by_obid, 
independent_isectElimination, 
isectElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
unionElimination, 
lambdaEquality, 
applyEquality, 
setElimination, 
rename, 
setEquality, 
independent_pairFormation, 
natural_numberEquality, 
computeAll, 
int_eqEquality, 
intEquality, 
inrFormation, 
dependent_pairFormation, 
functionEquality, 
productEquality, 
independent_pairEquality, 
minusEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
promote_hyp, 
applyLambdaEquality, 
levelHypothesis, 
addLevel, 
addEquality, 
inlFormation
Latex:
\mforall{}a,b,c:\mBbbR{}.  \mforall{}f:[a,  b]  {}\mrightarrow{}\mBbbR{}.
    (f[x]  continuous  for  x  \mmember{}  [a,  b]
    {}\mRightarrow{}  locally-non-constant(f;a;b;c)
    {}\mRightarrow{}  locally-non-constant-rational(f;a;b;c))
Date html generated:
2017_10_03-AM-10_30_55
Last ObjectModification:
2017_07_28-AM-08_12_12
Theory : reals
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