Nuprl Lemma : l_disjoint_singleton
∀[T:Type]. ∀[a:T List]. ∀[x:T].  uiff(l_disjoint(T;a;[x]);¬(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], 
l_disjoint: l_disjoint(T;l1;l2), 
uiff: uiff(P;Q), 
and: P ∧ Q, 
uimplies: b supposing a, 
member: t ∈ T, 
not: ¬A, 
implies: P ⇒ Q, 
false: False, 
prop: ℙ, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
cand: A c∧ B
Lemmas referenced : 
l_member_wf, 
all_wf, 
not_wf, 
equal_wf, 
member_singleton, 
cons_wf, 
nil_wf, 
uiff_wf, 
list_wf, 
and_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
cut, 
independent_pairFormation, 
introduction, 
lambdaFormation, 
thin, 
hypothesis, 
sqequalHypSubstitution, 
independent_functionElimination, 
voidElimination, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
dependent_functionElimination, 
productEquality, 
productElimination, 
because_Cache, 
addLevel, 
independent_isectElimination, 
cumulativity, 
universeEquality, 
hyp_replacement, 
equalitySymmetry, 
dependent_set_memberEquality, 
applyLambdaEquality, 
setElimination, 
rename
Latex:
\mforall{}[T:Type].  \mforall{}[a:T  List].  \mforall{}[x:T].    uiff(l\_disjoint(T;a;[x]);\mneg{}(x  \mmember{}  a))
Date html generated:
2019_06_20-PM-01_27_16
Last ObjectModification:
2018_08_24-PM-11_25_52
Theory : list_1
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