Nuprl Lemma : no_repeats-firstn
∀[T:Type]. ∀[l:T List].  ∀[n:ℤ]. no_repeats(T;firstn(n;l)) supposing no_repeats(T;l)
Proof
Definitions occuring in Statement : 
firstn: firstn(n;as), 
no_repeats: no_repeats(T;l), 
list: T List, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
int: ℤ, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
so_lambda: λ2x.t[x], 
uimplies: b supposing a, 
prop: ℙ, 
so_apply: x[s], 
implies: P ⇒ Q, 
firstn: firstn(n;as), 
all: ∀x:A. B[x], 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
top: Top, 
so_apply: x[s1;s2;s3], 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
ifthenelse: if b then t else f fi , 
cand: A c∧ B, 
bfalse: ff, 
exists: ∃x:A. B[x], 
or: P ∨ Q, 
sq_type: SQType(T), 
guard: {T}, 
bnot: ¬bb, 
assert: ↑b, 
false: False, 
not: ¬A
Lemmas referenced : 
list_induction, 
isect_wf, 
no_repeats_wf, 
uall_wf, 
firstn_wf, 
list_wf, 
list_ind_nil_lemma, 
no_repeats_witness, 
nil_wf, 
list_ind_cons_lemma, 
lt_int_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
no_repeats_cons, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
less_than_wf, 
no_repeats_nil, 
ifthenelse_wf, 
cons_wf, 
subtract_wf, 
member-firstn-implies-member, 
l_member_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
thin, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
cumulativity, 
hypothesis, 
intEquality, 
independent_functionElimination, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
because_Cache, 
lambdaFormation, 
rename, 
natural_numberEquality, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
independent_isectElimination, 
independent_pairFormation, 
dependent_pairFormation, 
promote_hyp, 
instantiate, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[l:T  List].    \mforall{}[n:\mBbbZ{}].  no\_repeats(T;firstn(n;l))  supposing  no\_repeats(T;l)
Date html generated:
2017_04_17-AM-07_29_17
Last ObjectModification:
2017_02_27-PM-04_07_28
Theory : list_1
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