Nuprl Lemma : continuous-abs-subtype
∀[I:Interval]. ∀[f:I ⟶ℝ].  (f[x] continuous for x ∈ I ⊆r |f[x]| continuous for x ∈ I)
Proof
Definitions occuring in Statement : 
continuous: f[x] continuous for x ∈ I
, 
rfun: I ⟶ℝ
, 
interval: Interval
, 
rabs: |x|
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
subtype_rel: A ⊆r B
, 
so_lambda: λ2x.t[x]
, 
label: ...$L... t
, 
rfun: I ⟶ℝ
, 
so_apply: x[s]
, 
prop: ℙ
, 
continuous-abs-ext, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
continuous: f[x] continuous for x ∈ I
, 
sq_exists: ∃x:{A| B[x]}
, 
and: P ∧ Q
, 
nat_plus: ℕ+
, 
uimplies: b supposing a
, 
rneq: x ≠ y
, 
guard: {T}
, 
or: P ∨ Q
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
rless: x < y
, 
decidable: Dec(P)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
not: ¬A
, 
top: Top
, 
squash: ↓T
, 
true: True
, 
sq_stable: SqStable(P)
, 
rleq: x ≤ y
, 
rnonneg: rnonneg(x)
, 
le: A ≤ B
Lemmas referenced : 
continuous_wf, 
i-member_wf, 
real_wf, 
rfun_wf, 
interval_wf, 
continuous-abs-ext, 
isect_wf, 
rabs_wf, 
equal_wf, 
nat_plus_wf, 
set_wf, 
icompact_wf, 
i-approx_wf, 
rless_wf, 
int-to-real_wf, 
less_than_wf, 
rleq_wf, 
rsub_wf, 
i-member-approx, 
rdiv_wf, 
rless-int, 
nat_plus_properties, 
decidable__lt, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformless_wf, 
itermConstant_wf, 
itermVar_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, 
squash_wf, 
true_wf, 
iff_weakening_equal, 
subtype_rel_dep_function, 
rmin_wf, 
rmin-idempotent-eq, 
sq_exists_wf, 
less_than'_wf, 
sq_stable__and, 
sq_stable__rless, 
sq_stable__all, 
sq_stable__rleq
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
lambdaEquality, 
rename, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
sqequalRule, 
applyEquality, 
setElimination, 
dependent_set_memberEquality, 
hypothesis, 
setEquality, 
axiomEquality, 
isect_memberEquality, 
because_Cache, 
instantiate, 
equalityTransitivity, 
equalitySymmetry, 
functionEquality, 
lambdaFormation, 
dependent_functionElimination, 
independent_functionElimination, 
isectEquality, 
functionExtensionality, 
productEquality, 
natural_numberEquality, 
independent_isectElimination, 
inrFormation, 
productElimination, 
unionElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
imageElimination, 
universeEquality, 
imageMemberEquality, 
baseClosed, 
hyp_replacement, 
applyLambdaEquality, 
minusEquality, 
independent_pairEquality
Latex:
\mforall{}[I:Interval].  \mforall{}[f:I  {}\mrightarrow{}\mBbbR{}].    (f[x]  continuous  for  x  \mmember{}  I  \msubseteq{}r  |f[x]|  continuous  for  x  \mmember{}  I)
Date html generated:
2017_10_03-AM-10_23_04
Last ObjectModification:
2017_07_28-AM-08_07_28
Theory : reals
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