Nuprl Lemma : member-reverse
∀[T:Type]. ∀L:T List. ∀x:T.  ((x ∈ rev(L)) 
⇐⇒ (x ∈ L))
Proof
Definitions occuring in Statement : 
l_member: (x ∈ l)
, 
reverse: rev(as)
, 
list: T List
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
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
, 
l_member: (x ∈ l)
, 
exists: ∃x:A. B[x]
, 
cand: A c∧ B
, 
member: t ∈ T
, 
prop: ℙ
, 
rev_implies: P 
⇐ Q
, 
squash: ↓T
, 
nat: ℕ
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
le: A ≤ B
, 
true: True
, 
subtype_rel: A ⊆r B
, 
uimplies: b supposing a
, 
guard: {T}
, 
top: Top
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
sq_stable: SqStable(P)
, 
subtract: n - m
, 
uiff: uiff(P;Q)
, 
nat_plus: ℕ+
, 
less_than: a < b
, 
less_than': less_than'(a;b)
, 
not: ¬A
, 
false: False
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
sq_type: SQType(T)
Lemmas referenced : 
l_member_wf, 
reverse_wf, 
list_wf, 
equal_wf, 
squash_wf, 
true_wf, 
select-reverse, 
lelt_wf, 
length_wf, 
iff_weakening_equal, 
length-reverse, 
subtract_wf, 
non_neg_length, 
length_wf_nat, 
nat_wf, 
set_subtype_base, 
le_wf, 
int_subtype_base, 
less_than_wf, 
select_wf, 
sq_stable__le, 
add-associates, 
minus-one-mul, 
add-swap, 
add-commutes, 
less-iff-le, 
add_functionality_wrt_le, 
le_reflexive, 
minus-one-mul-top, 
one-mul, 
add-mul-special, 
two-mul, 
mul-distributes-right, 
zero-mul, 
add-zero, 
not-le-2, 
minus-zero, 
zero-add, 
omega-shadow, 
mul-distributes, 
mul-associates, 
le-add-cancel, 
not-lt-2, 
minus-add, 
minus-minus, 
nat_properties, 
decidable__le, 
decidable__lt, 
subtype_base_sq
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
independent_pairFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
cut, 
introduction, 
extract_by_obid, 
isectElimination, 
cumulativity, 
hypothesisEquality, 
hypothesis, 
universeEquality, 
applyEquality, 
lambdaEquality, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
because_Cache, 
setElimination, 
rename, 
dependent_set_memberEquality, 
natural_numberEquality, 
sqequalRule, 
imageMemberEquality, 
baseClosed, 
independent_isectElimination, 
independent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
dependent_pairFormation, 
sqequalIntensionalEquality, 
intEquality, 
dependent_functionElimination, 
promote_hyp, 
productEquality, 
addLevel, 
addEquality, 
multiplyEquality, 
levelHypothesis, 
minusEquality, 
unionElimination, 
instantiate
Latex:
\mforall{}[T:Type].  \mforall{}L:T  List.  \mforall{}x:T.    ((x  \mmember{}  rev(L))  \mLeftarrow{}{}\mRightarrow{}  (x  \mmember{}  L))
Date html generated:
2017_04_14-AM-08_40_40
Last ObjectModification:
2017_02_27-PM-03_31_13
Theory : list_0
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