Nuprl Lemma : rinv-limit
∀x:ℕ ⟶ ℝ. ∀a:ℝ.  (lim n→∞.x[n] = a 
⇒ (∀n:ℕ. x[n] ≠ r0) 
⇒ a ≠ r0 
⇒ lim n→∞.(r1/x[n]) = (r1/a))
Proof
Definitions occuring in Statement : 
converges-to: lim n→∞.x[n] = y
, 
rdiv: (x/y)
, 
rneq: x ≠ y
, 
int-to-real: r(n)
, 
real: ℝ
, 
nat: ℕ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
converges-to: lim n→∞.x[n] = y
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
rev_uimplies: rev_uimplies(P;Q)
, 
uimplies: b supposing a
, 
req_int_terms: t1 ≡ t2
, 
false: False
, 
not: ¬A
, 
top: Top
, 
rsub: x - y
, 
rge: x ≥ y
, 
guard: {T}
, 
rneq: x ≠ y
, 
or: P ∨ Q
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
less_than: a < b
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
true: True
, 
nat_plus: ℕ+
, 
rless: x < y
, 
sq_exists: ∃x:A [B[x]]
, 
decidable: Dec(P)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
rdiv: (x/y)
, 
sq-all-large: ∀large(n).{P[n]}
, 
nat: ℕ
, 
rat_term_to_real: rat_term_to_real(f;t)
, 
rtermDivide: num "/" denom
, 
rat_term_ind: rat_term_ind, 
rtermVar: rtermVar(var)
, 
rtermConstant: "const"
, 
pi1: fst(t)
, 
rtermMultiply: left "*" right
, 
pi2: snd(t)
, 
ge: i ≥ j 
, 
subtype_rel: A ⊆r B
, 
absval: |i|
, 
cand: A c∧ B
, 
int_nzero: ℤ-o
, 
nequal: a ≠ b ∈ T 
, 
sq_type: SQType(T)
Lemmas referenced : 
rneq_wf, 
int-to-real_wf, 
istype-nat, 
converges-to_wf, 
real_wf, 
radd-preserves-rleq, 
rsub_wf, 
rabs_wf, 
radd_wf, 
rminus_wf, 
itermSubtract_wf, 
itermAdd_wf, 
itermVar_wf, 
itermMinus_wf, 
rleq_functionality, 
radd_functionality, 
req_weakening, 
rabs_functionality, 
req-iff-rsub-is-0, 
real_polynomial_null, 
istype-int, 
real_term_value_sub_lemma, 
istype-void, 
real_term_value_add_lemma, 
real_term_value_var_lemma, 
real_term_value_const_lemma, 
real_term_value_minus_lemma, 
rleq_weakening_equal, 
rabs-difference-symmetry, 
rleq_functionality_wrt_implies, 
r-triangle-inequality, 
rabs-neq-zero, 
rmul_preserves_rless, 
rdiv_wf, 
rless-int, 
rless_wf, 
rless-int-fractions2, 
nat_plus_properties, 
decidable__lt, 
full-omega-unsat, 
intformnot_wf, 
intformless_wf, 
itermConstant_wf, 
int_formula_prop_not_lemma, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_wf, 
istype-less_than, 
rmul_wf, 
rinv_wf2, 
itermMultiply_wf, 
rless_functionality, 
req_transitivity, 
rinv-mul-as-rdiv, 
real_term_value_mul_lemma, 
small-reciprocal-real, 
istype-le, 
assert-rat-term-eq2, 
rtermMultiply_wf, 
rtermDivide_wf, 
rtermConstant_wf, 
rtermVar_wf, 
rless_transitivity2, 
nat_properties, 
intformand_wf, 
int_formula_prop_and_lemma, 
int_term_value_var_lemma, 
radd-preserves-rless, 
squash_wf, 
true_wf, 
radd_comm_eq, 
subtype_rel_self, 
iff_weakening_equal, 
rmul-rinv3, 
radd_comm, 
nat_plus_wf, 
int_term_value_mul_lemma, 
rneq_functionality, 
rmul-int, 
rneq-int, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
set_subtype_base, 
less_than_wf, 
int_subtype_base, 
rmul_functionality, 
req_inversion, 
rinv_functionality2, 
rinv-of-rmul, 
sq-all-large-and, 
rleq_wf, 
rpositive-rless, 
rabs-positive, 
absval_wf, 
rabs-rmul, 
rabs-rdiv, 
rabs-int, 
rmul_preserves_rleq, 
rinv-as-rdiv, 
rmul-rinv, 
rleq_weakening_rless, 
rabs-rmul-rleq, 
square-nonzero, 
req-int-fractions, 
nequal_wf, 
nat_plus_inc_int_nzero, 
decidable__equal_int, 
req_functionality, 
rmul-rdiv-cancel5, 
int_entire_a, 
subtype_base_sq, 
rminus_functionality
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
sqequalHypSubstitution, 
cut, 
universeIsType, 
introduction, 
extract_by_obid, 
isectElimination, 
thin, 
hypothesisEquality, 
natural_numberEquality, 
hypothesis, 
sqequalRule, 
functionIsType, 
applyEquality, 
lambdaEquality_alt, 
because_Cache, 
productElimination, 
independent_isectElimination, 
dependent_functionElimination, 
approximateComputation, 
int_eqEquality, 
equalityTransitivity, 
equalitySymmetry, 
isect_memberEquality_alt, 
voidElimination, 
independent_functionElimination, 
closedConclusion, 
inrFormation_alt, 
independent_pairFormation, 
imageMemberEquality, 
baseClosed, 
dependent_set_memberEquality_alt, 
setElimination, 
rename, 
unionElimination, 
dependent_pairFormation_alt, 
inhabitedIsType, 
imageElimination, 
instantiate, 
universeEquality, 
multiplyEquality, 
equalityIstype, 
baseApply, 
intEquality, 
sqequalBase, 
cumulativity
Latex:
\mforall{}x:\mBbbN{}  {}\mrightarrow{}  \mBbbR{}.  \mforall{}a:\mBbbR{}.    (lim  n\mrightarrow{}\minfty{}.x[n]  =  a  {}\mRightarrow{}  (\mforall{}n:\mBbbN{}.  x[n]  \mneq{}  r0)  {}\mRightarrow{}  a  \mneq{}  r0  {}\mRightarrow{}  lim  n\mrightarrow{}\minfty{}.(r1/x[n])  =  (r1/a))
Date html generated:
2019_10_29-AM-10_22_43
Last ObjectModification:
2019_04_02-PM-04_08_58
Theory : reals
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