Nuprl Lemma : empty-bag-iff-size

∀[T:Type]. ∀[bs:bag(T)].  uiff(bs = {} ∈ bag(T);#(bs) ≤ 0)


Proof




Definitions occuring in Statement :  bag-size: #(bs),  empty-bag: {},  bag: bag(T),  uiff: uiff(P;Q),  uall: ∀[x:A]. B[x],  le: A ≤ B,  natural_number: $n,  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  uiff: uiff(P;Q),  and: P ∧ Q,  uimplies: b supposing a,  le: A ≤ B,  not: ¬A,  implies: P ⇒ Q,  false: False,  prop: ℙ,  subtype_rel: A ⊆r B,  nat: ℕ,  so_lambda: λ2x.t[x],  so_apply: x[s],  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  all: ∀x:A. B[x],  decidable: Dec(P),  or: P ∨ Q,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  top: Top,  squash: ↓T,  guard: {T},  less_than: a < b
Lemmas referenced :  bag_wf,  less_than'_wf,  bag-size_wf,  nat_wf,  equal-wf-T-base,  le_wf,  iff_weakening_uiff,  all_wf,  not_wf,  bag-member_wf,  empty-bag-iff-no-member,  uiff_wf,  decidable__le,  decidable__lt,  satisfiable-full-omega-tt,  intformand_wf,  intformnot_wf,  intformless_wf,  itermConstant_wf,  itermVar_wf,  intformle_wf,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_less_lemma,  int_term_value_constant_lemma,  int_term_value_var_lemma,  int_formula_prop_le_lemma,  int_formula_prop_wf,  bag-member-iff-size
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  sqequalRule,  sqequalHypSubstitution,  productElimination,  thin,  independent_pairEquality,  isect_memberEquality,  isectElimination,  hypothesisEquality,  lambdaEquality,  dependent_functionElimination,  because_Cache,  axiomEquality,  equalityTransitivity,  hypothesis,  equalitySymmetry,  extract_by_obid,  cumulativity,  voidElimination,  natural_numberEquality,  applyEquality,  setElimination,  rename,  baseClosed,  universeEquality,  addLevel,  independent_pairFormation,  independent_isectElimination,  independent_functionElimination,  instantiate,  lambdaFormation,  unionElimination,  dependent_pairFormation,  int_eqEquality,  intEquality,  voidEquality,  computeAll,  imageElimination,  imageMemberEquality

Latex:
\mforall{}[T:Type].  \mforall{}[bs:bag(T)].    uiff(bs  =  \{\};\#(bs)  \mleq{}  0)



Date html generated: 2017_10_01-AM-08_53_26
Last ObjectModification: 2017_07_26-PM-04_35_07

Theory : bags


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