Nuprl Lemma : set-equal-cons2
∀[T:Type]
  ∀eq:EqDecider(T). ∀u:T. ∀v,bs:T List.
    (set-equal(T;[u / v];bs) ⇐⇒ (u ∈ bs) ∧ set-equal(T;filter(λx.(¬b(eq x u));v);filter(λx.(¬b(eq x u));bs)))
Proof
Definitions occuring in Statement : 
set-equal: set-equal(T;x;y), 
l_member: (x ∈ l), 
filter: filter(P;l), 
cons: [a / b], 
list: T List, 
deq: EqDecider(T), 
bnot: ¬bb, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
apply: f a, 
lambda: λx.A[x], 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
implies: P ⇒ Q, 
set-equal: set-equal(T;x;y), 
member: t ∈ T, 
rev_implies: P ⇐ Q, 
or: P ∨ Q, 
prop: ℙ, 
deq: EqDecider(T), 
guard: {T}, 
not: ¬A, 
false: False, 
eqof: eqof(d), 
uiff: uiff(P;Q), 
uimplies: b supposing a, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
bfalse: ff, 
exists: ∃x:A. B[x], 
sq_type: SQType(T), 
bnot: ¬bb, 
ifthenelse: if b then t else f fi , 
assert: ↑b, 
cand: A c∧ B
Lemmas referenced : 
cons_member, 
l_member_wf, 
set-equal_wf, 
cons_wf, 
filter_wf5, 
bnot_wf, 
list_wf, 
deq_wf, 
or_wf, 
equal_wf, 
assert_witness, 
assert_wf, 
member_filter, 
iff_wf, 
eqof_wf, 
not_wf, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bnot, 
safe-assert-deq, 
bool_wf, 
eqtt_to_assert, 
and_wf, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
independent_pairFormation, 
sqequalHypSubstitution, 
cut, 
hypothesis, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
productElimination, 
independent_functionElimination, 
introduction, 
extract_by_obid, 
isectElimination, 
because_Cache, 
inlFormation, 
cumulativity, 
productEquality, 
lambdaEquality, 
applyEquality, 
setElimination, 
rename, 
setEquality, 
universeEquality, 
promote_hyp, 
sqequalRule, 
inrFormation, 
addLevel, 
impliesFunctionality, 
unionElimination, 
voidElimination, 
independent_isectElimination, 
levelHypothesis, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
hyp_replacement, 
dependent_set_memberEquality, 
applyLambdaEquality, 
dependent_pairFormation, 
instantiate
Latex:
\mforall{}[T:Type]
    \mforall{}eq:EqDecider(T).  \mforall{}u:T.  \mforall{}v,bs:T  List.
        (set-equal(T;[u  /  v];bs)
        \mLeftarrow{}{}\mRightarrow{}  (u  \mmember{}  bs)  \mwedge{}  set-equal(T;filter(\mlambda{}x.(\mneg{}\msubb{}(eq  x  u));v);filter(\mlambda{}x.(\mneg{}\msubb{}(eq  x  u));bs)))
Date html generated:
2017_04_17-AM-07_37_16
Last ObjectModification:
2017_02_27-PM-04_12_15
Theory : list_1
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