Nuprl Lemma : l_disjoint_singleton2
∀[T:Type]. ∀[a:T List]. ∀[x:T].  uiff(l_disjoint(T;[x];a);¬(x ∈ a))
Proof
Definitions occuring in Statement : 
l_disjoint: l_disjoint(T;l1;l2), 
l_member: (x ∈ l), 
cons: [a / b], 
nil: [], 
list: T List, 
uiff: uiff(P;Q), 
uall: ∀[x:A]. B[x], 
not: ¬A, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
uimplies: b supposing a, 
implies: P ⇒ Q, 
iff: P ⇐⇒ Q, 
not: ¬A, 
false: False, 
prop: ℙ, 
rev_implies: P ⇐ Q, 
l_disjoint: l_disjoint(T;l1;l2), 
all: ∀x:A. B[x]
Lemmas referenced : 
l_disjoint_singleton, 
iff_weakening_uiff, 
l_disjoint_wf, 
cons_wf, 
nil_wf, 
l_disjoint-symmetry, 
l_member_wf, 
and_wf, 
not_wf, 
uiff_wf, 
list_wf
Rules used in proof : 
cut, 
lemma_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
addLevel, 
productElimination, 
independent_pairFormation, 
introduction, 
independent_isectElimination, 
independent_functionElimination, 
sqequalRule, 
lambdaEquality, 
dependent_functionElimination, 
voidElimination, 
cumulativity, 
because_Cache, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[a:T  List].  \mforall{}[x:T].    uiff(l\_disjoint(T;[x];a);\mneg{}(x  \mmember{}  a))
Date html generated:
2016_05_14-AM-07_55_50
Last ObjectModification:
2015_12_26-PM-04_49_56
Theory : list_1
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