Testing the Supermodular-Cut Condition
For a function on a finite set V with f (∅)= f ( V )=0, a digraph D =( V , A ) is called f -connected if it satisfies the f -cut condition, that is, δ D ( X )≥ f ( X ) for any X ⊆ V , where δ D ( X ) is the number of arcs from X to V ∖ X . We show that, for any crossing supermodular function f , the...
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| Veröffentlicht in: | Algorithmica Jg. 71; H. 4; S. 1065 - 1075 |
|---|---|
| Hauptverfasser: | , |
| Format: | Journal Article |
| Sprache: | Englisch |
| Veröffentlicht: |
Boston
Springer US
01.04.2015
|
| Schlagworte: | |
| ISSN: | 0178-4617, 1432-0541 |
| Online-Zugang: | Volltext |
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| Zusammenfassung: | For a function
on a finite set
V
with
f
(∅)=
f
(
V
)=0, a digraph
D
=(
V
,
A
) is called
f
-connected if it satisfies the
f
-cut condition, that is,
δ
D
(
X
)≥
f
(
X
) for any
X
⊆
V
, where
δ
D
(
X
) is the number of arcs from
X
to
V
∖
X
. We show that, for any crossing supermodular function
f
, the
f
-connectivity can be tested with a constant number of queries in the general digraph model with average degree bound. As immediate corollaries, we obtain constant-time testers for
k
-edge-connectivity, rooted-(
k
,
l
)-edge-connectivity, and the property of having
k
arc-disjoint arborescences. We also give a corresponding result for the undirected case. |
|---|---|
| ISSN: | 0178-4617 1432-0541 |
| DOI: | 10.1007/s00453-013-9842-8 |