Nuprl Lemma : remove-repeats_property
∀[T:Type]
  ∀eq:EqDecider(T). ∀L:T List.  (no_repeats(T;remove-repeats(eq;L)) ∧ (∀a:T. ((a ∈ remove-repeats(eq;L)) ⇐⇒ (a ∈ L))))
Proof
Definitions occuring in Statement : 
remove-repeats: remove-repeats(eq;L), 
no_repeats: no_repeats(T;l), 
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], 
member: t ∈ T, 
so_lambda: λ2x.t[x], 
prop: ℙ, 
and: P ∧ Q, 
so_apply: x[s], 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
implies: P ⇒ Q, 
remove-repeats: remove-repeats(eq;L), 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
top: Top, 
so_apply: x[s1;s2;s3], 
cand: A c∧ B, 
deq: EqDecider(T), 
uiff: uiff(P;Q), 
uimplies: b supposing a, 
not: ¬A, 
false: False, 
eqof: eqof(d), 
or: P ∨ Q, 
guard: {T}, 
decidable: Dec(P)
Lemmas referenced : 
list_induction, 
no_repeats_wf, 
remove-repeats_wf, 
all_wf, 
iff_wf, 
l_member_wf, 
list_wf, 
list_ind_nil_lemma, 
no_repeats_nil, 
nil_wf, 
list_ind_cons_lemma, 
no_repeats_cons, 
filter_wf5, 
bnot_wf, 
no_repeats_filter, 
cons_wf, 
deq_wf, 
member_filter, 
not_wf, 
assert_wf, 
member_wf, 
eqof_wf, 
equal_wf, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bnot, 
safe-assert-deq, 
cons_member, 
decidable-equal-deq
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
thin, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
productEquality, 
cumulativity, 
hypothesis, 
independent_functionElimination, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
because_Cache, 
rename, 
productElimination, 
applyEquality, 
setElimination, 
setEquality, 
independent_isectElimination, 
universeEquality, 
addLevel, 
impliesFunctionality, 
andLevelFunctionality, 
levelHypothesis, 
impliesLevelFunctionality, 
unionElimination, 
inlFormation, 
inrFormation
Latex:
\mforall{}[T:Type]
    \mforall{}eq:EqDecider(T).  \mforall{}L:T  List.
        (no\_repeats(T;remove-repeats(eq;L))  \mwedge{}  (\mforall{}a:T.  ((a  \mmember{}  remove-repeats(eq;L))  \mLeftarrow{}{}\mRightarrow{}  (a  \mmember{}  L))))
Date html generated:
2017_04_17-AM-09_10_16
Last ObjectModification:
2017_02_27-PM-05_18_28
Theory : decidable!equality
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