Nuprl Lemma : fseg_member
∀[T:Type]. ∀l1,l2:T List. ∀x:T.  (fseg(T;l1;l2) 
⇒ (x ∈ l1) 
⇒ (x ∈ l2))
Proof
Definitions occuring in Statement : 
fseg: fseg(T;L1;L2)
, 
l_member: (x ∈ l)
, 
list: T List
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
fseg: fseg(T;L1;L2)
, 
exists: ∃x:A. B[x]
, 
member: t ∈ T
, 
prop: ℙ
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
guard: {T}
, 
or: P ∨ Q
Lemmas referenced : 
length_wf_nat, 
equal_wf, 
nat_wf, 
member_append, 
l_member_wf, 
fseg_wf, 
list_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
cut, 
dependent_set_memberEquality, 
hypothesis, 
introduction, 
extract_by_obid, 
isectElimination, 
cumulativity, 
hypothesisEquality, 
because_Cache, 
dependent_functionElimination, 
independent_functionElimination, 
sqequalRule, 
inrFormation, 
hyp_replacement, 
equalitySymmetry, 
Error :applyLambdaEquality, 
setElimination, 
rename, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}l1,l2:T  List.  \mforall{}x:T.    (fseg(T;l1;l2)  {}\mRightarrow{}  (x  \mmember{}  l1)  {}\mRightarrow{}  (x  \mmember{}  l2))
Date html generated:
2016_10_25-AM-10_45_32
Last ObjectModification:
2016_07_12-AM-06_54_56
Theory : general
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