Nuprl Lemma : bag-member-implies-hd-append

∀[T:Type]. ∀[x:T]. ∀[b:bag(T)].  ↓∃c:bag(T). (b = ({x} + c) ∈ bag(T)) supposing x ↓∈ b


Proof




Definitions occuring in Statement :  bag-member: x ↓∈ bs,  bag-append: as + bs,  single-bag: {x},  bag: bag(T),  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  exists: ∃x:A. B[x],  squash: ↓T,  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  uimplies: b supposing a,  squash: ↓T,  exists: ∃x:A. B[x],  prop: ℙ,  bag-member: x ↓∈ bs,  and: P ∧ Q,  l_member: (x ∈ l),  cand: A c∧ B,  nat: ℕ,  subtype_rel: A ⊆r B,  single-bag: {x},  bag-append: as + bs,  append: as @ bs,  all: ∀x:A. B[x],  so_lambda: so_lambda(x,y,z.t[x; y; z]),  top: Top,  so_apply: x[s1;s2;s3],  bag: bag(T),  so_lambda: λ2x y.t[x; y],  so_apply: x[s1;s2],  ge: i ≥ j ,  decidable: Dec(P),  or: P ∨ Q,  satisfiable_int_formula: satisfiable_int_formula(fmla),  false: False,  implies: P ⇒ Q,  not: ¬A,  so_lambda: λ2x.t[x],  so_apply: x[s],  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  int_seg: {i..j-},  lelt: i ≤ j < k,  le: A ≤ B,  int_iseg: {i...j}
Lemmas referenced :  bag_to_squash_list,  bag-member_wf,  reject_wf,  list-subtype-bag,  list_ind_cons_lemma,  list_ind_nil_lemma,  quotient-member-eq,  list_wf,  permutation_wf,  permutation-equiv,  cons_wf,  select_wf,  nat_properties,  decidable__le,  satisfiable-full-omega-tt,  intformand_wf,  intformnot_wf,  intformle_wf,  itermConstant_wf,  itermVar_wf,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_le_lemma,  int_term_value_constant_lemma,  int_term_value_var_lemma,  int_formula_prop_wf,  equal_wf,  bag_wf,  bag-append_wf,  single-bag_wf,  squash_wf,  exists_wf,  permutation_inversion,  permutation-cons,  firstn_nth_tl_decomp,  lelt_wf,  length_wf,  firstn_wf,  nth_tl_wf,  append_wf,  permutation_weakening,  reject_eq_firstn_nth_tl,  length-append,  length_firstn,  length_of_cons_lemma,  intformless_wf,  int_formula_prop_less_lemma,  le_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  because_Cache,  hypothesisEquality,  imageElimination,  productElimination,  promote_hyp,  hypothesis,  equalitySymmetry,  hyp_replacement,  applyLambdaEquality,  cumulativity,  rename,  dependent_pairFormation,  setElimination,  applyEquality,  independent_isectElimination,  lambdaEquality,  sqequalRule,  dependent_functionElimination,  isect_memberEquality,  voidElimination,  voidEquality,  natural_numberEquality,  unionElimination,  int_eqEquality,  intEquality,  independent_pairFormation,  computeAll,  independent_functionElimination,  imageMemberEquality,  baseClosed,  equalityTransitivity,  universeEquality,  dependent_set_memberEquality,  addEquality,  productEquality

Latex:
\mforall{}[T:Type].  \mforall{}[x:T].  \mforall{}[b:bag(T)].    \mdownarrow{}\mexists{}c:bag(T).  (b  =  (\{x\}  +  c))  supposing  x  \mdownarrow{}\mmember{}  b



Date html generated: 2017_10_01-AM-08_55_47
Last ObjectModification: 2017_07_26-PM-04_37_53

Theory : bags


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