Nuprl Lemma : rnonzero-iff
∀x:ℝ. (rnonzero(x) ⇐⇒ x ≠ r0)
Proof
Definitions occuring in Statement : 
rneq: x ≠ y, 
rnonzero: rnonzero(x), 
int-to-real: r(n), 
real: ℝ, 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
natural_number: $n
Definitions unfolded in proof : 
int-to-real: r(n), 
rneq: x ≠ y, 
rnonzero: rnonzero(x), 
rless: x < y, 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
implies: P ⇒ Q, 
exists: ∃x:A. B[x], 
member: t ∈ T, 
prop: ℙ, 
uall: ∀[x:A]. B[x], 
so_lambda: λ2x.t[x], 
real: ℝ, 
subtype_rel: A ⊆r B, 
nat: ℕ, 
so_apply: x[s], 
rev_implies: P ⇐ Q, 
or: P ∨ Q, 
sq_exists: ∃x:{A| B[x]}, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
uiff: uiff(P;Q), 
uimplies: b supposing a, 
less_than: a < b, 
less_than': less_than'(a;b), 
top: Top, 
true: True, 
squash: ↓T, 
not: ¬A, 
false: False, 
nat_plus: ℕ+, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
bfalse: ff, 
sq_type: SQType(T), 
guard: {T}, 
bnot: ¬bb, 
ifthenelse: if b then t else f fi , 
assert: ↑b, 
decidable: Dec(P)
Lemmas referenced : 
exists_wf, 
nat_plus_wf, 
less_than_wf, 
absval_wf, 
nat_wf, 
absval_unfold, 
lt_int_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
top_wf, 
nat_plus_properties, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformless_wf, 
itermConstant_wf, 
itermVar_wf, 
itermAdd_wf, 
itermMultiply_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_term_value_add_lemma, 
int_term_value_mul_lemma, 
int_formula_prop_wf, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
decidable__lt, 
add-is-int-iff, 
intformnot_wf, 
itermMinus_wf, 
int_formula_prop_not_lemma, 
int_term_value_minus_lemma, 
false_wf, 
or_wf, 
sq_exists_wf, 
real_wf, 
absval_ifthenelse, 
assert_wf, 
bnot_wf, 
not_wf, 
bool_cases, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bnot, 
minus-is-int-iff
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
sqequalRule, 
lambdaFormation, 
independent_pairFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
cut, 
introduction, 
extract_by_obid, 
isectElimination, 
hypothesis, 
lambdaEquality, 
natural_numberEquality, 
applyEquality, 
setElimination, 
rename, 
hypothesisEquality, 
unionElimination, 
dependent_pairFormation, 
because_Cache, 
minusEquality, 
equalityElimination, 
independent_isectElimination, 
lessCases, 
isect_memberFormation, 
sqequalAxiom, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
independent_functionElimination, 
int_eqEquality, 
intEquality, 
dependent_functionElimination, 
computeAll, 
equalityTransitivity, 
equalitySymmetry, 
promote_hyp, 
instantiate, 
cumulativity, 
dependent_set_memberEquality, 
pointwiseFunctionality, 
baseApply, 
closedConclusion, 
addEquality, 
multiplyEquality, 
impliesFunctionality, 
inrFormation, 
dependent_set_memberFormation, 
inlFormation
Latex:
\mforall{}x:\mBbbR{}.  (rnonzero(x)  \mLeftarrow{}{}\mRightarrow{}  x  \mneq{}  r0)
Date html generated:
2017_10_03-AM-08_27_04
Last ObjectModification:
2017_07_28-AM-07_24_40
Theory : reals
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