Nuprl Lemma : l_before_append_front
∀[T:Type]. ∀L1,L2:T List. ∀x,y:T.  x before y ∈ L1 @ L2 ⇒ x before y ∈ L1 supposing ¬(y ∈ L2)
Proof
Definitions occuring in Statement : 
l_before: x before y ∈ l, 
l_member: (x ∈ l), 
append: as @ bs, 
list: T List, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
not: ¬A, 
implies: P ⇒ Q, 
universe: Type
Definitions unfolded in proof : 
l_before: x before y ∈ l, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
uimplies: b supposing a, 
member: t ∈ T, 
not: ¬A, 
implies: P ⇒ Q, 
false: False, 
prop: ℙ, 
top: Top, 
assert: ↑b, 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
last: last(L), 
select: L[n], 
cons: [a / b], 
subtract: n - m, 
length: ||as||, 
list_ind: list_ind, 
nil: [], 
it: ⋅
Lemmas referenced : 
l_member_wf, 
sublist_append_front, 
cons_wf, 
nil_wf, 
null_cons_lemma, 
last_wf, 
not_wf, 
assert_wf, 
null_wf, 
sublist_wf, 
append_wf, 
list_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
lambdaFormation, 
cut, 
introduction, 
sqequalHypSubstitution, 
lambdaEquality, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
voidElimination, 
lemma_by_obid, 
isectElimination, 
hypothesis, 
rename, 
because_Cache, 
independent_isectElimination, 
isect_memberEquality, 
voidEquality, 
independent_functionElimination, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}L1,L2:T  List.  \mforall{}x,y:T.    x  before  y  \mmember{}  L1  @  L2  {}\mRightarrow{}  x  before  y  \mmember{}  L1  supposing  \mneg{}(y  \mmember{}  L2)
Date html generated:
2016_05_14-AM-07_44_54
Last ObjectModification:
2015_12_26-PM-02_53_05
Theory : list_1
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