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: t ∈ T
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T uiff: uiff(P;Q) and: P ∧ Q uimplies: supposing a le: A ≤ B not: ¬A implies:  Q false: False prop: subtype_rel: A ⊆B nat: so_lambda: λ2x.t[x] so_apply: x[s] iff: ⇐⇒ Q rev_implies:  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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