Nuprl Lemma : firstn-firstn

[L:Top List]. ∀[n:ℕ]. ∀[m:ℕn].  (firstn(m;firstn(n;L)) firstn(m;L))


Proof




Definitions occuring in Statement :  firstn: firstn(n;as) list: List int_seg: {i..j-} nat: uall: [x:A]. B[x] top: Top natural_number: $n sqequal: t
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T all: x:A. B[x] nat: implies:  Q false: False and: P ∧ Q ge: i ≥  le: A ≤ B cand: c∧ B less_than: a < b squash: T guard: {T} uimplies: supposing a prop: or: P ∨ Q firstn: firstn(n;as) so_lambda: so_lambda3 so_apply: x[s1;s2;s3] cons: [a b] less_than': less_than'(a;b) not: ¬A colength: colength(L) nil: [] it: so_lambda: λ2x.t[x] so_apply: x[s] sq_type: SQType(T) so_lambda: λ2y.t[x; y] so_apply: x[s1;s2] sq_stable: SqStable(P) decidable: Dec(P) iff: ⇐⇒ Q rev_implies:  Q uiff: uiff(P;Q) subtract: m true: True subtype_rel: A ⊆B int_seg: {i..j-} lelt: i ≤ j < k bool: 𝔹 unit: Unit btrue: tt ifthenelse: if then else fi  bfalse: ff exists: x:A. B[x] bnot: ¬bb assert: b
Lemmas referenced :  nat_properties less_than_transitivity1 less_than_irreflexivity ge_wf istype-less_than top_wf list-cases list_ind_nil_lemma int_seg_wf product_subtype_list colength-cons-not-zero istype-nat colength_wf_list istype-void istype-le list_wf subtract-1-ge-0 subtype_base_sq nat_wf set_subtype_base le_wf int_subtype_base spread_cons_lemma sq_stable__le decidable__equal_int subtract_wf istype-false not-equal-2 condition-implies-le add-associates minus-add minus-one-mul add-swap minus-one-mul-top le_antisymmetry_iff add_functionality_wrt_le add-commutes zero-add le-add-cancel minus-minus list_ind_cons_lemma lt_int_wf eqtt_to_assert assert_of_lt_int decidable__le not-le-2 less-iff-le add-zero decidable__lt not-lt-2 le-add-cancel-alt eqff_to_assert bool_cases_sqequal bool_subtype_base assert-bnot iff_weakening_uiff assert_wf less_than_wf le_weakening2
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation_alt introduction cut thin lambdaFormation_alt extract_by_obid sqequalHypSubstitution isectElimination hypothesisEquality hypothesis setElimination rename intWeakElimination independent_pairFormation productElimination imageElimination natural_numberEquality independent_isectElimination independent_functionElimination voidElimination universeIsType sqequalRule lambdaEquality_alt dependent_functionElimination isect_memberEquality_alt axiomSqEquality isectIsTypeImplies inhabitedIsType functionIsTypeImplies unionElimination Error :memTop,  because_Cache promote_hyp hypothesis_subsumption equalityIstype dependent_set_memberEquality_alt instantiate cumulativity intEquality equalityTransitivity equalitySymmetry imageMemberEquality baseClosed applyLambdaEquality addEquality minusEquality baseApply closedConclusion applyEquality sqequalBase equalityElimination productIsType dependent_pairFormation_alt

Latex:
\mforall{}[L:Top  List].  \mforall{}[n:\mBbbN{}].  \mforall{}[m:\mBbbN{}n].    (firstn(m;firstn(n;L))  \msim{}  firstn(m;L))



Date html generated: 2020_05_19-PM-09_37_31
Last ObjectModification: 2020_03_05-AM-10_59_27

Theory : list_0


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