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Rainbow Matchings and Algebras of Sets
Grinblat (Algebras of Sets and Combinatorics, Translations of Mathematical Monographs, vol. 214. AMS, Providence, 2002 ) asks the following question in the context of algebras of sets: What is the smallest number v = v ( n ) such that, if A 1 , … , A n are n equivalence relations on a common finite...
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Published in: | Graphs and combinatorics 2017-03, Vol.33 (2), p.473-484 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Grinblat (Algebras of Sets and Combinatorics, Translations of Mathematical Monographs, vol. 214. AMS, Providence,
2002
) asks the following question in the context of algebras of sets: What is the smallest number
v
=
v
(
n
)
such that, if
A
1
,
…
,
A
n
are
n
equivalence relations on a common finite ground set
X
, such that for each
i
there are at least
v
elements of
X
that belong to
A
i
-equivalence classes of size larger than 1, then
X
has a rainbow matching—a set of 2
n
distinct elements
a
1
,
b
1
,
…
,
a
n
,
b
n
, such that
a
i
is
A
i
-equivalent to
b
i
for each
i
? Grinblat has shown that
v
(
n
)
≤
10
n
/
3
+
O
(
n
)
. He asks whether
v
(
n
)
=
3
n
-
2
for all
n
≥
4
. In this paper we improve the upper bound (for all large enough
n
) to
v
(
n
)
≤
16
n
/
5
+
O
(
1
)
. |
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ISSN: | 0911-0119 1435-5914 |
DOI: | 10.1007/s00373-017-1764-9 |