Nuprl Lemma : no_repeats_cons

[T:Type]. ∀[l:T List]. ∀[x:T].  uiff(no_repeats(T;[x l]);no_repeats(T;l) ∧ (x ∈ l)))


Proof




Definitions occuring in Statement :  no_repeats: no_repeats(T;l) l_member: (x ∈ l) cons: [a b] list: List uiff: uiff(P;Q) uall: [x:A]. B[x] not: ¬A and: P ∧ Q universe: Type
Definitions unfolded in proof :  no_repeats: no_repeats(T;l) all: x:A. B[x] member: t ∈ T top: Top uall: [x:A]. B[x] uiff: uiff(P;Q) and: P ∧ Q uimplies: supposing a not: ¬A implies:  Q false: False nat: sq_stable: SqStable(P) squash: T prop: true: True less_than': less_than'(a;b) le: A ≤ B subtype_rel: A ⊆B subtract: m rev_implies:  Q iff: ⇐⇒ Q or: P ∨ Q decidable: Dec(P) guard: {T} l_member: (x ∈ l) exists: x:A. B[x] cand: c∧ B select: L[n] cons: [a b] sq_type: SQType(T) label: ...$L... t
Lemmas referenced :  length_of_cons_lemma istype-void select_wf sq_stable__le not_wf equal_wf nat_wf less_than_wf length_wf l_member_wf cons_wf list_wf le_antisymmetry_iff not-equal-2 decidable__equal_int le-add-cancel2 less-iff-le not-lt-2 decidable__lt le_wf le-add-cancel add-zero add_functionality_wrt_le add-commutes add-swap add-associates minus-one-mul-top zero-add minus-one-mul minus-add condition-implies-le not-le-2 false_wf decidable__le squash_wf true_wf select_cons_tl iff_weakening_equal istype-false istype-int int_subtype_base subtract_wf minus-minus subtype_rel_self minus-zero le-add-cancel-alt subtype_base_sq
Rules used in proof :  sqequalSubstitution sqequalRule sqequalReflexivity sqequalTransitivity computationStep cut introduction extract_by_obid sqequalHypSubstitution dependent_functionElimination thin Error :isect_memberEquality_alt,  voidElimination hypothesis Error :isect_memberFormation_alt,  independent_pairFormation Error :lambdaFormation_alt,  independent_functionElimination Error :equalityIsType1,  Error :inhabitedIsType,  hypothesisEquality isectElimination cumulativity setElimination rename because_Cache independent_isectElimination natural_numberEquality imageMemberEquality baseClosed imageElimination Error :lambdaEquality_alt,  Error :universeIsType,  equalityTransitivity equalitySymmetry productElimination independent_pairEquality Error :isectIsType,  addEquality Error :productIsType,  universeEquality applyLambdaEquality minusEquality intEquality voidEquality isect_memberEquality lambdaEquality applyEquality lambdaFormation unionElimination dependent_set_memberEquality Error :dependent_set_memberEquality_alt,  Error :equalityIsType4,  instantiate Error :dependent_pairFormation_alt,  promote_hyp

Latex:
\mforall{}[T:Type].  \mforall{}[l:T  List].  \mforall{}[x:T].    uiff(no\_repeats(T;[x  /  l]);no\_repeats(T;l)  \mwedge{}  (\mneg{}(x  \mmember{}  l)))



Date html generated: 2019_06_20-PM-00_42_15
Last ObjectModification: 2018_10_01-PM-10_15_57

Theory : list_0


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