Nuprl Lemma : rnonzero_functionality
∀x,y:ℝ.  ((x = y) ⇒ (rnonzero(x) ⇐⇒ rnonzero(y)))
Proof
Definitions occuring in Statement : 
rnonzero: rnonzero(x), 
req: x = y, 
real: ℝ, 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
implies: P ⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
member: t ∈ T, 
prop: ℙ, 
uall: ∀[x:A]. B[x], 
real: ℝ, 
rnonzero: rnonzero(x), 
exists: ∃x:A. B[x], 
uimplies: b supposing a, 
nat_plus: ℕ+, 
subtype_rel: A ⊆r B, 
nat: ℕ, 
decidable: Dec(P), 
or: P ∨ Q, 
less_than: a < b, 
squash: ↓T, 
and: P ∧ Q, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
false: False, 
not: ¬A, 
top: Top, 
less_than': less_than'(a;b), 
true: True, 
req: x = y, 
le: A ≤ B, 
uiff: uiff(P;Q), 
rev_uimplies: rev_uimplies(P;Q), 
ge: i ≥ j , 
guard: {T}, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q
Lemmas referenced : 
rnonzero_wf, 
req_wf, 
real_wf, 
rnonzero-lemma1, 
nat_plus_properties, 
decidable__le, 
absval_wf, 
less_than_wf, 
nat_wf, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
mul_nat_plus, 
itermMultiply_wf, 
int_term_value_mul_lemma, 
subtract_wf, 
multiply-is-int-iff, 
false_wf, 
decidable__equal_int, 
intformeq_wf, 
itermAdd_wf, 
itermSubtract_wf, 
int_formula_prop_eq_lemma, 
int_term_value_add_lemma, 
int_term_value_subtract_lemma, 
and_wf, 
equal_wf, 
le_wf, 
le_functionality, 
le_weakening, 
int-triangle-inequality, 
mul_cancel_in_le, 
decidable__lt, 
add-is-int-iff, 
req_inversion
Rules used in proof : 
cut, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
setElimination, 
rename, 
hypothesisEquality, 
hypothesis, 
productElimination, 
independent_isectElimination, 
dependent_functionElimination, 
natural_numberEquality, 
applyEquality, 
dependent_set_memberEquality, 
lambdaEquality, 
sqequalRule, 
unionElimination, 
imageElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
imageMemberEquality, 
baseClosed, 
because_Cache, 
independent_functionElimination, 
multiplyEquality, 
addEquality, 
pointwiseFunctionality, 
equalityTransitivity, 
equalitySymmetry, 
promote_hyp, 
baseApply, 
closedConclusion, 
setEquality, 
hyp_replacement, 
Error :applyLambdaEquality
Latex:
\mforall{}x,y:\mBbbR{}.    ((x  =  y)  {}\mRightarrow{}  (rnonzero(x)  \mLeftarrow{}{}\mRightarrow{}  rnonzero(y)))
 Date html generated: 
2016_10_26-AM-09_04_12
 Last ObjectModification: 
2016_07_12-AM-08_14_38
Theory : reals
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