Nuprl Lemma : l_disjoint_cons
∀[T:Type]. ∀[a,b:T List]. ∀[x:T].  uiff(l_disjoint(T;a;[x / b]);(¬(x ∈ a)) ∧ l_disjoint(T;a;b))
Proof
Definitions occuring in Statement : 
l_disjoint: l_disjoint(T;l1;l2)
, 
l_member: (x ∈ l)
, 
cons: [a / b]
, 
list: T List
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
not: ¬A
, 
and: P ∧ Q
, 
universe: Type
Definitions unfolded in proof : 
append: as @ bs
, 
all: ∀x:A. B[x]
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
member: t ∈ T
, 
top: Top
, 
so_apply: x[s1;s2;s3]
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
false: False
, 
prop: ℙ
, 
uall: ∀[x:A]. B[x]
, 
l_disjoint: l_disjoint(T;l1;l2)
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
l_member_wf, 
and_wf, 
not_wf, 
l_disjoint_wf, 
l_disjoint_singleton, 
cons_wf, 
nil_wf, 
uiff_wf, 
iff_weakening_uiff, 
append_wf, 
l_disjoint_append, 
list_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
hypothesis, 
independent_pairFormation, 
isect_memberFormation, 
introduction, 
lambdaFormation, 
productElimination, 
independent_functionElimination, 
isectElimination, 
hypothesisEquality, 
independent_pairEquality, 
lambdaEquality, 
because_Cache, 
addLevel, 
independent_isectElimination, 
cumulativity, 
universeEquality, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}[T:Type].  \mforall{}[a,b:T  List].  \mforall{}[x:T].    uiff(l\_disjoint(T;a;[x  /  b]);(\mneg{}(x  \mmember{}  a))  \mwedge{}  l\_disjoint(T;a;b))
Date html generated:
2016_05_14-AM-07_56_09
Last ObjectModification:
2015_12_26-PM-04_50_30
Theory : list_1
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