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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