Nuprl Lemma : case-real_wf
∀[P:ℙ]. ∀[a,b:ℝ]. ∀[f:{n:ℕ+| 4 < |(a n) - b n|}  ⟶ ((↓P) ∨ (↓¬P))].
  (case-real(a;b;f) ∈ {z:ℝ| (P 
⇒ (z = a)) ∧ ((¬P) 
⇒ (z = b))} )
Proof
Definitions occuring in Statement : 
case-real: case-real(a;b;f)
, 
req: x = y
, 
real: ℝ
, 
absval: |i|
, 
nat_plus: ℕ+
, 
less_than: a < b
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
not: ¬A
, 
squash: ↓T
, 
implies: P 
⇒ Q
, 
or: P ∨ Q
, 
and: P ∧ Q
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
subtract: n - m
, 
natural_number: $n
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
real: ℝ
, 
case-real: case-real(a;b;f)
, 
subtype_rel: A ⊆r B
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
nat: ℕ
, 
band: p ∧b q
, 
ifthenelse: if b then t else f fi 
, 
or: P ∨ Q
, 
bfalse: ff
, 
exists: ∃x:A. B[x]
, 
sq_type: SQType(T)
, 
guard: {T}
, 
bnot: ¬bb
, 
assert: ↑b
, 
false: False
, 
not: ¬A
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
prop: ℙ
, 
regular-int-seq: k-regular-seq(f)
, 
squash: ↓T
, 
nat_plus: ℕ+
, 
decidable: Dec(P)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
top: Top
, 
rev_uimplies: rev_uimplies(P;Q)
, 
ge: i ≥ j 
, 
true: True
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
cand: A c∧ B
, 
stable: Stable{P}
, 
rneq: x ≠ y
, 
int_upper: {i...}
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
gt: i > j
, 
less_than: a < b
, 
req: x = y
, 
bdd-diff: bdd-diff(f;g)
, 
absval: |i|
, 
subtract: n - m
Lemmas referenced : 
lt_int_wf, 
absval_wf, 
subtract_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
istype-less_than, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
assert-bnot, 
iff_weakening_uiff, 
assert_wf, 
less_than_wf, 
nat_plus_wf, 
squash_wf, 
not_wf, 
real_wf, 
nat_plus_properties, 
decidable__le, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermMultiply_wf, 
itermConstant_wf, 
itermAdd_wf, 
itermVar_wf, 
intformless_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_mul_lemma, 
int_term_value_constant_lemma, 
int_term_value_add_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
le_functionality, 
le_weakening, 
int-triangle-inequality, 
int_subtype_base, 
decidable__equal_int, 
decidable__lt, 
intformeq_wf, 
itermSubtract_wf, 
int_formula_prop_eq_lemma, 
int_term_value_subtract_lemma, 
mul_preserves_le, 
le_wf, 
true_wf, 
absval_mul, 
subtype_rel_self, 
iff_weakening_equal, 
nat_wf, 
set_subtype_base, 
absval-non-neg, 
equal_wf, 
istype-universe, 
left_mul_subtract_distrib, 
istype-le, 
mul-commutes, 
absval_pos, 
nat_plus_subtype_nat, 
add_functionality_wrt_le, 
absval-diff-symmetry, 
add-commutes, 
accelerate_wf, 
regular-int-seq_wf, 
real-regular, 
req_wf, 
stable_req, 
false_wf, 
minimal-double-negation-hyp-elim, 
minimal-not-not-excluded-middle, 
req-iff-bdd-diff, 
eventually-equal-implies-bdd-diff, 
bdd-diff_functionality, 
accelerate-bdd-diff, 
bdd-diff_weakening, 
rneq-iff, 
rless-iff4, 
absval_lbound, 
int_upper_properties, 
gt_wf, 
istype-int_upper, 
subtype_rel_sets_simple, 
less_than_transitivity1, 
req_functionality, 
req_weakening, 
istype-false, 
minus-one-mul, 
add-mul-special, 
zero-mul, 
le_weakening2
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
sqequalHypSubstitution, 
setElimination, 
thin, 
rename, 
lambdaEquality_alt, 
extract_by_obid, 
isectElimination, 
natural_numberEquality, 
applyEquality, 
hypothesisEquality, 
hypothesis, 
because_Cache, 
sqequalRule, 
inhabitedIsType, 
lambdaFormation_alt, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
independent_isectElimination, 
dependent_set_memberEquality_alt, 
equalityIstype, 
dependent_functionElimination, 
independent_functionElimination, 
dependent_pairFormation_alt, 
promote_hyp, 
instantiate, 
cumulativity, 
voidElimination, 
universeIsType, 
axiomEquality, 
functionIsType, 
setIsType, 
unionIsType, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
universeEquality, 
imageElimination, 
multiplyEquality, 
addEquality, 
approximateComputation, 
int_eqEquality, 
independent_pairFormation, 
intEquality, 
imageMemberEquality, 
baseClosed, 
productIsType, 
unionEquality, 
productEquality, 
functionEquality, 
inlFormation_alt, 
minusEquality, 
pointwiseFunctionality, 
inrFormation_alt, 
sqequalBase
Latex:
\mforall{}[P:\mBbbP{}].  \mforall{}[a,b:\mBbbR{}].  \mforall{}[f:\{n:\mBbbN{}\msupplus{}|  4  <  |(a  n)  -  b  n|\}    {}\mrightarrow{}  ((\mdownarrow{}P)  \mvee{}  (\mdownarrow{}\mneg{}P))].
    (case-real(a;b;f)  \mmember{}  \{z:\mBbbR{}|  (P  {}\mRightarrow{}  (z  =  a))  \mwedge{}  ((\mneg{}P)  {}\mRightarrow{}  (z  =  b))\}  )
Date html generated:
2019_10_29-AM-09_36_43
Last ObjectModification:
2019_05_23-PM-05_35_58
Theory : reals
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