Nuprl Lemma : l_before_append_iff

[T:Type]. ∀A,B:T List. ∀x,y:T.  (x before y ∈ ⇐⇒ before y ∈ A ∨ before y ∈ B ∨ ((x ∈ A) ∧ (y ∈ B)))


Proof




Definitions occuring in Statement :  l_before: before y ∈ l l_member: (x ∈ l) append: as bs list: List uall: [x:A]. B[x] all: x:A. B[x] iff: ⇐⇒ Q or: P ∨ Q and: P ∧ Q universe: Type
Definitions unfolded in proof :  rev_implies:  Q iff: ⇐⇒ Q implies:  Q so_apply: x[s] and: P ∧ Q or: P ∨ Q prop: so_lambda: λ2x.t[x] member: t ∈ T all: x:A. B[x] uall: [x:A]. B[x] append: as bs so_lambda: so_lambda(x,y,z.t[x; y; z]) top: Top so_apply: x[s1;s2;s3] guard: {T} uimplies: supposing a not: ¬A false: False cand: c∧ B
Lemmas referenced :  istype-universe l_member_wf append_wf l_before_wf iff_wf list_wf list_induction list_ind_nil_lemma nil_wf or_wf null_nil_lemma btrue_wf member-implies-null-eq-bfalse btrue_neq_bfalse nil_before cons_wf list_ind_cons_lemma istype-void cons_before cons_member member_append
Rules used in proof :  universeEquality instantiate dependent_functionElimination unionIsType productIsType because_Cache functionIsType rename independent_functionElimination universeIsType productEquality unionEquality hypothesis functionEquality lambdaEquality_alt sqequalRule hypothesisEquality isectElimination sqequalHypSubstitution extract_by_obid introduction thin cut lambdaFormation_alt isect_memberFormation_alt sqequalReflexivity computationStep sqequalTransitivity sqequalSubstitution isect_memberEquality voidElimination voidEquality lambdaFormation independent_pairFormation inrFormation inlFormation cumulativity unionElimination productElimination independent_isectElimination equalityTransitivity equalitySymmetry inhabitedIsType equalityIstype isect_memberEquality_alt inlFormation_alt inrFormation_alt promote_hyp

Latex:
\mforall{}[T:Type]
    \mforall{}A,B:T  List.  \mforall{}x,y:T.
        (x  before  y  \mmember{}  A  @  B  \mLeftarrow{}{}\mRightarrow{}  x  before  y  \mmember{}  A  \mvee{}  x  before  y  \mmember{}  B  \mvee{}  ((x  \mmember{}  A)  \mwedge{}  (y  \mmember{}  B)))



Date html generated: 2019_10_15-AM-10_21_41
Last ObjectModification: 2019_08_05-PM-02_08_48

Theory : list_1


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