Nuprl Lemma : Troelstra-lemma

¬(∀g:ℕ ⟶ ℕ. ∃n:ℕ. ∀f:ℕ ⟶ ℕ((f g ∈ (ℕn ⟶ ℕ))  (∀x:ℕ((g x) 0 ∈ ℕ))  (∀x:ℕ((f x) 0 ∈ ℕ))))


Proof




Definitions occuring in Statement :  int_seg: {i..j-} nat: all: x:A. B[x] exists: x:A. B[x] not: ¬A implies:  Q apply: a function: x:A ⟶ B[x] natural_number: $n equal: t ∈ T
Definitions unfolded in proof :  not: ¬A implies:  Q all: x:A. B[x] member: t ∈ T nat: le: A ≤ B and: P ∧ Q less_than': less_than'(a;b) false: False prop: uall: [x:A]. B[x] exists: x:A. B[x] so_lambda: λ2x.t[x] subtype_rel: A ⊆B uimplies: supposing a so_apply: x[s] less_than: a < b true: True squash: T top: Top int_seg: {i..j-} bool: 𝔹 unit: Unit it: btrue: tt uiff: uiff(P;Q) guard: {T} ge: i ≥  lelt: i ≤ j < k decidable: Dec(P) or: P ∨ Q satisfiable_int_formula: satisfiable_int_formula(fmla) bfalse: ff sq_type: SQType(T) bnot: ¬bb ifthenelse: if then else fi  assert: b iff: ⇐⇒ Q rev_implies:  Q
Lemmas referenced :  false_wf le_wf nat_wf all_wf exists_wf equal_wf int_seg_wf subtype_rel_function int_seg_subtype_nat subtype_rel_self equal-wf-T-base less_than_wf lt_int_wf bool_wf eqtt_to_assert assert_of_lt_int top_wf int_seg_properties nat_properties decidable__equal_int full-omega-unsat intformnot_wf intformeq_wf itermConstant_wf int_formula_prop_not_lemma int_formula_prop_eq_lemma int_term_value_constant_lemma int_formula_prop_wf eqff_to_assert bool_cases_sqequal subtype_base_sq bool_subtype_base assert-bnot intformand_wf intformless_wf itermVar_wf int_formula_prop_and_lemma int_formula_prop_less_lemma int_term_value_var_lemma int_subtype_base zero-le-nat squash_wf true_wf iff_weakening_equal decidable__le intformle_wf itermAdd_wf int_formula_prop_le_lemma int_term_value_add_lemma equal-wf-base
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity lambdaFormation cut hypothesis sqequalHypSubstitution dependent_functionElimination thin lambdaEquality dependent_set_memberEquality natural_numberEquality sqequalRule independent_pairFormation introduction extract_by_obid isectElimination hypothesisEquality productElimination functionEquality setElimination rename applyEquality because_Cache independent_isectElimination baseClosed lessCases equalityTransitivity equalitySymmetry imageMemberEquality isect_memberFormation axiomSqEquality isect_memberEquality voidElimination voidEquality imageElimination independent_functionElimination functionExtensionality unionElimination equalityElimination approximateComputation dependent_pairFormation intEquality promote_hyp instantiate cumulativity int_eqEquality universeEquality addEquality applyLambdaEquality

Latex:
\mneg{}(\mforall{}g:\mBbbN{}  {}\mrightarrow{}  \mBbbN{}.  \mexists{}n:\mBbbN{}.  \mforall{}f:\mBbbN{}  {}\mrightarrow{}  \mBbbN{}.  ((f  =  g)  {}\mRightarrow{}  (\mforall{}x:\mBbbN{}.  ((g  x)  =  0))  {}\mRightarrow{}  (\mforall{}x:\mBbbN{}.  ((f  x)  =  0))))



Date html generated: 2019_06_20-PM-02_49_34
Last ObjectModification: 2018_08_20-PM-09_32_57

Theory : fan-theorem


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