Nuprl Lemma : member-intersection

∀[A:Type]. ∀eq:EqDecider(A). ∀L1,L2:A List. ∀x:A.  ((x ∈ l_intersection(eq;L1;L2)) ⇐⇒ (x ∈ L1) ∧ (x ∈ L2))


Proof




Definitions occuring in Statement :  l_intersection: l_intersection(eq;L1;L2),  l_member: (x ∈ l),  list: T List,  deq: EqDecider(T),  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  and: P ∧ Q,  universe: Type
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  l_intersection: l_intersection(eq;L1;L2),  iff: P ⇐⇒ Q,  and: P ∧ Q,  member: t ∈ T,  implies: P ⇒ Q,  prop: ℙ,  rev_implies: P ⇐ Q
Lemmas referenced :  assert-deq-member,  assert_wf,  deq-member_wf,  iff_wf,  and_wf,  l_member_wf,  member_filter,  filter_wf5,  list_wf,  deq_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  lambdaFormation,  cut,  sqequalRule,  addLevel,  sqequalHypSubstitution,  productElimination,  thin,  independent_pairFormation,  impliesFunctionality,  hypothesis,  lemma_by_obid,  isectElimination,  because_Cache,  dependent_functionElimination,  hypothesisEquality,  independent_functionElimination,  andLevelFunctionality,  lambdaEquality,  cumulativity,  setElimination,  rename,  setEquality,  universeEquality

Latex:
\mforall{}[A:Type]
    \mforall{}eq:EqDecider(A).  \mforall{}L1,L2:A  List.  \mforall{}x:A.    ((x  \mmember{}  l\_intersection(eq;L1;L2))  \mLeftarrow{}{}\mRightarrow{}  (x  \mmember{}  L1)  \mwedge{}  (x  \mmember{}  L2))



Date html generated: 2016_05_14-PM-03_32_30
Last ObjectModification: 2015_12_26-PM-06_01_25

Theory : decidable!equality


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