Research Article
On Subdirect Decompositions of Finite Distributive Lattices
Yizhi Chen,
1
Jing Tian,
2
and Zhongzhu Liu
1
1
School of Mathematics and Big Data, Huizhou University, Huizhou, Guangdong 516007, China
2
School of Economics and Finance, Xi’an International Studies University, Xi’an, Shaanxi 710128, China
Correspondence should be addressed to Yizhi Chen; yizhichen1980@126.com
Received 18 January 2017; Accepted 2 April 2017; Published 27 April 2017
Ac
ademicEditor:J.R.Torregrosa
Copyright © 2017 Yizhi Chen et al. is is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Subdirect decomposition of algebra is one of its quite general and important constructions. In this paper, some subdirect
decompositions (including subdirect irreducible decompositions) of nite distributive lattices and nite chains are studied, and
some general results are obtained.
1. Introduction and Preliminaries
A semiring is an algebraic structure (,+,⋅)consisting of
a nonempty set together with two binary operations + and
⋅ on such that (,+) and (,⋅) are semigroups connected
by distributivity, that is, ( + ) = + and ( + ) =
+,forall,, ∈ [1, 2]. A semiring is called a partially
ordered semiring if it admits a compatible ordering ≤,thatis,
≤ is a partial order on satisfying the following condition:
for any ,,, ∈ ,if≤and ≤,then+≤+and
≤ . A partially ordered semiring is said to be a totally
ordered semiring if the imposed partial order is a total order
[1, 2].
A distributive lattice is a lattice which satises the dis-
tributive laws [3]. In the following, we will denote =
,+,⋅,0,1as a nite distributive lattice, where 0 and 1 are
theleastandthegreatestelementsof,respectively,andthe
addition and the multiplication on are dened as follows:
+=∨=max
{
,
}
,
⋅=∧=min
{
,
}
∀, ∈ .
(1)
Also, we denote ={0,1,...,}as a nite chain with usual
ordering [4]. Clearly, both the nite distributive lattices and
the nite chains are partially ordered semirings.
A semiring issaidtobeasubdirectproductofan
indexed family
𝑖
( ∈ )ofsemiringsifitsatises≤Π
𝑖∈𝐼
𝑖
and
𝑖
=
𝑖
for each ∈.
An embedding :→Π
𝑖∈𝐼
𝑖
is subdirect if is
asubdirectproductof
𝑖
.Atthistime,wealsosaythat
has subdirect decomposition of
𝑖
or is isomorphic to the
subdirect product of {
𝑖
}
𝑖∈𝐼
.
A semiring is called subdirectly irreducible if for every
subdirect embedding :→Π
𝑖∈𝐼
𝑖
,thereisan∈such
that
𝑖
:→
𝑖
is an isomorphism. From the above
denition, it is easy to see that any two-element semiring is
subdirectly irreducible.
From [4–7] we know that the subdirect product is a quite
general construction. As for as semirings concerned, there
are several ways of approaching subdirect decompositions of
semirings. In most cases they can be obtained from various
semirings theoretical constructions. Another way is based
on the famous Birkho representation theorem. Formulated
in terms of semirings, it asserts that every semiring can be
represented as a subdirect product of subdirectly irreducible
semirings, and it can oen reduce studying the structure
of semirings from a given class to studying subdirectly
irreducible members of this class. Also, there is a third way
of approaching subdirect decompositions which is based on
another Birkho theorem veried in [4], which, in terms of
semirings, says that a semiring isasubdirectproductofa
family of semirings {
𝑖
}
𝑖∈𝐼
if and only if there exists a family
of factor congruences {
𝑖
}
𝑖∈𝐼
on such that
𝑖∈𝐼
𝑖
=
𝑅
and
/
𝑖
=
𝑖
for each ∈;here,
𝑅
is the identity congruence
on .
e main aim of this paper is to investigate the subdirect
decompositions of a special class of semirings called nite
Hindawi
Discrete Dynamics in Nature and Society
Volume 2017, Article ID 6490903, 5 pages
https://doi.org/10.1155/2017/6490903