Nuprl Lemma : real-fun-iff-continuous
∀a,b:ℝ.  ∀f:[a, b] ⟶ℝ. (real-fun(f;a;b) ⇐⇒ real-cont(f;a;b)) supposing a ≤ b
Proof
Definitions occuring in Statement : 
real-cont: real-cont(f;a;b), 
real-fun: real-fun(f;a;b), 
rfun: I ⟶ℝ, 
rccint: [l, u], 
rleq: x ≤ y, 
real: ℝ, 
uimplies: b supposing a, 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
rleq: x ≤ y, 
rnonneg: rnonneg(x), 
uall: ∀[x:A]. B[x], 
le: A ≤ B, 
and: P ∧ Q, 
iff: P ⇐⇒ Q, 
implies: P ⇒ Q, 
prop: ℙ, 
rev_implies: P ⇐ Q, 
real-fun: real-fun(f;a;b), 
so_lambda: λ2x.t[x], 
rfun: I ⟶ℝ, 
subtype_rel: A ⊆r B, 
so_apply: x[s], 
continuous: f[x] continuous for x ∈ I, 
i-approx: i-approx(I;n), 
rccint: [l, u], 
real-cont: real-cont(f;a;b), 
exists: ∃x:A. B[x], 
sq_exists: ∃x:A [B[x]], 
cand: A c∧ B, 
sq_stable: SqStable(P), 
squash: ↓T, 
rev_uimplies: rev_uimplies(P;Q), 
nat_plus: ℕ+, 
rneq: x ≠ y, 
guard: {T}, 
or: P ∨ Q, 
rless: x < y, 
decidable: Dec(P), 
not: ¬A, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
false: False, 
top: Top, 
rge: x ≥ y, 
uiff: uiff(P;Q), 
req_int_terms: t1 ≡ t2
Lemmas referenced : 
real-continuity, 
le_witness_for_triv, 
real-fun_wf, 
continuous-rneq, 
rccint_wf, 
subtype_rel_self, 
rfun_wf, 
req_wf, 
i-member_wf, 
real-cont_wf, 
rleq_wf, 
real_wf, 
nat_plus_wf, 
icompact_wf, 
i-approx_wf, 
sq_stable__rless, 
int-to-real_wf, 
rleq_functionality_wrt_implies, 
rabs_wf, 
rsub_wf, 
rdiv_wf, 
rless-int, 
nat_plus_properties, 
decidable__lt, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformless_wf, 
itermConstant_wf, 
itermVar_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_not_lemma, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
rless_wf, 
rleq_weakening_equal, 
rleq_weakening, 
itermSubtract_wf, 
req-iff-rsub-is-0, 
real_polynomial_null, 
real_term_value_sub_lemma, 
real_term_value_var_lemma, 
real_term_value_const_lemma, 
req-iff-not-rneq, 
rneq_wf
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
hypothesis, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
isect_memberFormation_alt, 
sqequalRule, 
lambdaEquality_alt, 
isectElimination, 
productElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_isectElimination, 
functionIsTypeImplies, 
inhabitedIsType, 
rename, 
independent_pairFormation, 
universeIsType, 
applyEquality, 
independent_functionElimination, 
setElimination, 
setIsType, 
dependent_set_memberFormation_alt, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
dependent_set_memberEquality_alt, 
because_Cache, 
closedConclusion, 
inrFormation_alt, 
unionElimination, 
approximateComputation, 
dependent_pairFormation_alt, 
int_eqEquality, 
isect_memberEquality_alt, 
voidElimination, 
productIsType, 
functionIsType
Latex:
\mforall{}a,b:\mBbbR{}.    \mforall{}f:[a,  b]  {}\mrightarrow{}\mBbbR{}.  (real-fun(f;a;b)  \mLeftarrow{}{}\mRightarrow{}  real-cont(f;a;b))  supposing  a  \mleq{}  b
Date html generated:
2019_10_30-AM-07_15_21
Last ObjectModification:
2019_10_09-PM-05_37_58
Theory : reals
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