Nuprl Lemma : primrec-induction-factorial

∀n:ℕ. (∃x:ℤ [((n)! = x ∈ ℤ)])


Proof




Definitions occuring in Statement :  fact: (n)!,  nat: ℕ,  all: ∀x:A. B[x],  sq_exists: ∃x:A [B[x]],  int: ℤ,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  so_lambda: λ2x.t[x],  member: t ∈ T,  subtype_rel: A ⊆r B,  nat_plus: ℕ+,  so_apply: x[s],  implies: P ⇒ Q,  all: ∀x:A. B[x],  prop: ℙ,  sq_exists: ∃x:A [B[x]],  has-value: (a)↓,  uimplies: b supposing a,  nat: ℕ,  not: ¬A,  ge: i ≥ j ,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  false: False,  top: Top,  and: P ∧ Q,  squash: ↓T,  true: True,  guard: {T},  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  decidable: Dec(P),  or: P ∨ Q
Lemmas referenced :  primrec-induction,  sq_exists_wf,  equal-wf-T-base,  fact_wf,  nat_plus_wf,  int_subtype_base,  nat_wf,  fact0_redex_lemma,  equal-wf-base,  value-type-has-value,  int-value-type,  fact_unroll_1,  nat_properties,  satisfiable-full-omega-tt,  intformand_wf,  intformeq_wf,  itermAdd_wf,  itermVar_wf,  itermConstant_wf,  intformle_wf,  int_formula_prop_and_lemma,  int_formula_prop_eq_lemma,  int_term_value_add_lemma,  int_term_value_var_lemma,  int_term_value_constant_lemma,  int_formula_prop_le_lemma,  int_formula_prop_wf,  add-subtract-cancel,  equal_wf,  squash_wf,  true_wf,  iff_weakening_equal,  decidable__le,  intformnot_wf,  int_formula_prop_not_lemma,  le_wf
Rules used in proof :  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isectElimination,  thin,  sqequalRule,  lambdaEquality,  intEquality,  hypothesisEquality,  hypothesis,  applyEquality,  setElimination,  rename,  independent_functionElimination,  lambdaFormation,  because_Cache,  dependent_set_memberFormation,  natural_numberEquality,  baseClosed,  callbyvalueReduce,  independent_isectElimination,  addEquality,  multiplyEquality,  dependent_pairFormation,  int_eqEquality,  dependent_functionElimination,  isect_memberEquality,  voidElimination,  voidEquality,  independent_pairFormation,  computeAll,  imageElimination,  equalityTransitivity,  equalitySymmetry,  universeEquality,  imageMemberEquality,  productElimination,  dependent_set_memberEquality,  unionElimination

Latex:
\mforall{}n:\mBbbN{}.  (\mexists{}x:\mBbbZ{}  [((n)!  =  x)])



Date html generated: 2018_05_21-PM-06_59_42
Last ObjectModification: 2017_07_26-PM-05_02_10

Theory : general


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