Nuprl Lemma : Cauchy-equation-1-iff
∀[f:ℝ ⟶ ℝ]
  uiff(∀x,y:ℝ.  (f(x + y) = (f(x) + f(y)));∀x:ℝ. (f(x) = (x * f(r1)))) supposing ∀x,y:ℝ.  ((x = y) 
⇒ ((f x) = (f y)))
Proof
Definitions occuring in Statement : 
rfun-ap: f(x)
, 
req: x = y
, 
rmul: a * b
, 
radd: a + b
, 
int-to-real: r(n)
, 
real: ℝ
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
Definitions unfolded in proof : 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
prop: ℙ
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
and: P ∧ Q
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
rev_uimplies: rev_uimplies(P;Q)
, 
req_int_terms: t1 ≡ t2
, 
nequal: a ≠ b ∈ T 
, 
less_than': less_than'(a;b)
, 
assert: ↑b
, 
bnot: ¬bb
, 
sq_type: SQType(T)
, 
unit: Unit
, 
bool: 𝔹
, 
guard: {T}
, 
or: P ∨ Q
, 
decidable: Dec(P)
, 
int-to-real: r(n)
, 
btrue: tt
, 
eq_int: (i =z j)
, 
length: ||as||
, 
radd-list: radd-list(L)
, 
it: ⋅
, 
nil: []
, 
bfalse: ff
, 
lt_int: i <z j
, 
ifthenelse: if b then t else f fi 
, 
from-upto: [n, m)
, 
list_ind: list_ind, 
map: map(f;as)
, 
evalall: evalall(t)
, 
callbyvalueall: callbyvalueall, 
subtract: n - m
, 
rsum: Σ{x[k] | n≤k≤m}
, 
lelt: i ≤ j < k
, 
int_seg: {i..j-}
, 
le: A ≤ B
, 
top: Top
, 
exists: ∃x:A. B[x]
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
not: ¬A
, 
ge: i ≥ j 
, 
false: False
, 
nat: ℕ
, 
rdiv: (x/y)
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
rneq: x ≠ y
, 
nat_plus: ℕ+
, 
subtype_rel: A ⊆r B
, 
squash: ↓T
, 
true: True
, 
rfun-ap: f(x)
, 
r-ap: f(x)
, 
rfun: I ⟶ℝ
, 
less_than: a < b
Lemmas referenced : 
radd_wf, 
req_wf, 
all_wf, 
int-to-real_wf, 
rmul_wf, 
rfun-ap_wf, 
req_witness, 
real_wf, 
radd_functionality, 
req_transitivity, 
rsum_unroll, 
real_term_value_minus_lemma, 
real_term_value_const_lemma, 
real_term_value_mul_lemma, 
real_term_value_var_lemma, 
real_term_value_add_lemma, 
real_term_value_sub_lemma, 
real_polynomial_null, 
req_weakening, 
int_term_value_add_lemma, 
neg_assert_of_eq_int, 
false_wf, 
assert_of_eq_int, 
eq_int_wf, 
assert-bnot, 
bool_subtype_base, 
subtype_base_sq, 
bool_cases_sqequal, 
equal_wf, 
eqff_to_assert, 
assert_of_lt_int, 
eqtt_to_assert, 
bool_wf, 
lt_int_wf, 
itermMinus_wf, 
req-iff-rsub-is-0, 
itermMultiply_wf, 
itermAdd_wf, 
req_inversion, 
radd-rminus-both, 
rminus_wf, 
radd-preserves-req, 
radd-zero, 
rfun-ap_functionality, 
req_functionality, 
nat_wf, 
decidable__lt, 
int_term_value_subtract_lemma, 
int_formula_prop_not_lemma, 
itermSubtract_wf, 
intformnot_wf, 
decidable__le, 
lelt_wf, 
subtract-add-cancel, 
int_seg_wf, 
subtract_wf, 
rsum_wf, 
less_than_wf, 
ge_wf, 
int_formula_prop_wf, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_and_lemma, 
intformless_wf, 
itermVar_wf, 
itermConstant_wf, 
intformle_wf, 
intformand_wf, 
full-omega-unsat, 
nat_properties, 
rinv-mul-as-rdiv, 
rmul_functionality, 
rmul-rinv3, 
uiff_transitivity, 
assert_of_bnot, 
iff_weakening_uiff, 
iff_transitivity, 
bool_cases, 
rsum-constant2, 
rmul_preserves_req, 
rinv_wf2, 
not_wf, 
bnot_wf, 
assert_wf, 
rsub_wf, 
req-implies-req, 
le_wf, 
set_subtype_base, 
rmul_comm, 
int_formula_prop_eq_lemma, 
intformeq_wf, 
decidable__equal_int, 
int_subtype_base, 
ifthenelse_wf, 
nat_plus_wf, 
rless_wf, 
nat_plus_properties, 
rless-int, 
rdiv_wf, 
nat_plus_subtype_nat, 
rdiv_functionality, 
rmul-one, 
radd_comm, 
radd-rminus, 
rminus-int, 
true_wf, 
squash_wf, 
rminus_functionality, 
rmul-rinv, 
int_term_value_minus_lemma, 
rminus-rminus, 
set_wf, 
subtype_rel_self, 
subtype_rel_dep_function, 
i-member_wf, 
exists_wf, 
rneq_wf, 
member_riiint_lemma, 
riiint_wf, 
functions-equal-on-rationals, 
rmul-distrib2
Rules used in proof : 
functionEquality, 
equalitySymmetry, 
equalityTransitivity, 
isect_memberEquality, 
independent_pairEquality, 
productElimination, 
because_Cache, 
independent_functionElimination, 
natural_numberEquality, 
applyEquality, 
functionExtensionality, 
isectElimination, 
hypothesisEquality, 
thin, 
dependent_functionElimination, 
lambdaEquality, 
sqequalHypSubstitution, 
sqequalRule, 
hypothesis, 
extract_by_obid, 
lambdaFormation, 
independent_pairFormation, 
cut, 
introduction, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
cumulativity, 
instantiate, 
promote_hyp, 
equalityElimination, 
unionElimination, 
addEquality, 
dependent_set_memberEquality, 
voidEquality, 
voidElimination, 
intEquality, 
int_eqEquality, 
dependent_pairFormation, 
approximateComputation, 
independent_isectElimination, 
intWeakElimination, 
rename, 
setElimination, 
impliesFunctionality, 
inrFormation, 
baseClosed, 
imageMemberEquality, 
imageElimination, 
minusEquality, 
setEquality, 
inlFormation
Latex:
\mforall{}[f:\mBbbR{}  {}\mrightarrow{}  \mBbbR{}]
    uiff(\mforall{}x,y:\mBbbR{}.    (f(x  +  y)  =  (f(x)  +  f(y)));\mforall{}x:\mBbbR{}.  (f(x)  =  (x  *  f(r1)))) 
    supposing  \mforall{}x,y:\mBbbR{}.    ((x  =  y)  {}\mRightarrow{}  ((f  x)  =  (f  y)))
Date html generated:
2017_10_04-PM-11_02_35
Last ObjectModification:
2017_07_31-PM-00_33_16
Theory : reals_2
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