Nuprl Lemma : rational_fun_zero_wf
∀a,b:ℝ. ∀f:(ℤ × ℕ+) ⟶ (ℤ × ℕ+).
  ∀[g:{x:ℝ| x ∈ [a, b]}  ⟶ ℝ]
    rational_fun_zero(f;a;b) ∈ {c:ℝ| (c ∈ (a, b)) ∧ (g[c] = r0)}  
    supposing (a < b)
    ∧ ((g[a] * g[b]) < r0)
    ∧ (∀x,y:{x:ℝ| x ∈ [a, b]} .  ((x = y) 
⇒ (g[x] = g[y])))
    ∧ (∀r:ℤ × ℕ+. ((ratreal(r) ∈ [a, b]) 
⇒ (g[ratreal(r)] = ratreal(f[r]))))
Proof
Definitions occuring in Statement : 
rational_fun_zero: rational_fun_zero(f;a;b)
, 
ratreal: ratreal(r)
, 
rooint: (l, u)
, 
rccint: [l, u]
, 
i-member: r ∈ I
, 
rless: x < y
, 
req: x = y
, 
rmul: a * b
, 
int-to-real: r(n)
, 
real: ℝ
, 
nat_plus: ℕ+
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
function: x:A ⟶ B[x]
, 
product: x:A × B[x]
, 
natural_number: $n
, 
int: ℤ
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
uall: ∀[x:A]. B[x]
, 
uimplies: b supposing a
, 
member: t ∈ T
, 
rational-IVT-ext, 
rational_fun_zero: rational_fun_zero(f;a;b)
, 
mu-ge: mu-ge(f;n)
, 
ifthenelse: if b then t else f fi 
, 
band: p ∧b q
, 
le_int: i ≤z j
, 
bnot: ¬bb
, 
lt_int: i <z j
, 
and: P ∧ Q
, 
top: Top
, 
so_apply: x[s]
, 
sq_exists: ∃x:A [B[x]]
, 
implies: P 
⇒ Q
, 
subtype_rel: A ⊆r B
, 
i-member: r ∈ I
, 
rccint: [l, u]
, 
rooint: (l, u)
, 
so_lambda: λ2x.t[x]
, 
prop: ℙ
, 
cand: A c∧ B
, 
guard: {T}
, 
sq_stable: SqStable(P)
, 
squash: ↓T
Lemmas referenced : 
rational-IVT-ext, 
member_rccint_lemma, 
istype-void, 
member_rooint_lemma, 
real_wf, 
subtype_rel_self, 
all_wf, 
uall_wf, 
rleq_wf, 
isect_wf, 
rless_wf, 
rmul_wf, 
rleq_weakening_equal, 
rleq_weakening_rless, 
int-to-real_wf, 
req_wf, 
nat_plus_wf, 
ratreal_wf, 
sq_exists_wf, 
subtype_rel_sets, 
subtype_rel_sets_simple, 
i-member_wf, 
rccint_wf, 
sq_stable__rless, 
istype-int
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
isect_memberFormation_alt, 
cut, 
thin, 
instantiate, 
extract_by_obid, 
hypothesis, 
sqequalRule, 
sqequalHypSubstitution, 
productElimination, 
applyEquality, 
introduction, 
dependent_functionElimination, 
isect_memberEquality_alt, 
voidElimination, 
functionExtensionality, 
hypothesisEquality, 
because_Cache, 
isectElimination, 
functionEquality, 
lambdaEquality_alt, 
setEquality, 
productEquality, 
inhabitedIsType, 
setElimination, 
rename, 
independent_isectElimination, 
independent_pairFormation, 
dependent_set_memberEquality_alt, 
productIsType, 
universeIsType, 
closedConclusion, 
natural_numberEquality, 
setIsType, 
intEquality, 
functionIsType, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
equalityIstype
Latex:
\mforall{}a,b:\mBbbR{}.  \mforall{}f:(\mBbbZ{}  \mtimes{}  \mBbbN{}\msupplus{})  {}\mrightarrow{}  (\mBbbZ{}  \mtimes{}  \mBbbN{}\msupplus{}).
    \mforall{}[g:\{x:\mBbbR{}|  x  \mmember{}  [a,  b]\}    {}\mrightarrow{}  \mBbbR{}]
        rational\_fun\_zero(f;a;b)  \mmember{}  \{c:\mBbbR{}|  (c  \mmember{}  (a,  b))  \mwedge{}  (g[c]  =  r0)\}   
        supposing  (a  <  b)
        \mwedge{}  ((g[a]  *  g[b])  <  r0)
        \mwedge{}  (\mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  [a,  b]\}  .    ((x  =  y)  {}\mRightarrow{}  (g[x]  =  g[y])))
        \mwedge{}  (\mforall{}r:\mBbbZ{}  \mtimes{}  \mBbbN{}\msupplus{}.  ((ratreal(r)  \mmember{}  [a,  b])  {}\mRightarrow{}  (g[ratreal(r)]  =  ratreal(f[r]))))
Date html generated:
2019_10_30-AM-10_05_39
Last ObjectModification:
2019_01_14-PM-00_34_14
Theory : reals
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