Abstract and Applied Analysis

Volume 2013 (2013), Article ID 675373, 6 pages

http://dx.doi.org/10.1155/2013/675373

Research Article

Computing Hypercrossed Complex Pairings in Digital Images

Simge Öztunç, Ali Mutlu, and Necdet Bildik

Mathematics Department, Faculty of Science and Arts, Celal Bayar University, 45047 Manisa, Turkey

Received 3 October 2013; Accepted 9 November 2013

Academic Editor: Abdon Atangana

Copyright © 2013 Simge Öztunç et al. This 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.

Abstract.

We consider an additive group structure in digital images and introduce the commutator in digital images. Then we calculate the hypercrossed complex pairings which generates a normal subgroup in dimension 2 and in dimension 3 by using 8-adjacency and 26-adjacency.

1. Introduction

In this paper we denote the set of integers by . Then represents the set of lattice points in Euclidean -dimensional spaces. A finite subset of with an adjacency relation is called a digital image.

Definition 1 (see [1, 2]). Consider the following.

(1)Two points and in are 2-adjacent if .(2)Two points and in are 8-adjacent if they are distinct and differ by at most 1 in each coordinate.(3)Two points and in are 4-adjacent if they are 8-adjacent and differ by exactly one coordinate.(4)Two points and in are 26-adjacent if they are distinct and differ by at most 1 in each coordinate.(5)Two points and in are 18-adjacent if they are 26-adjacent and differ in at most two coordinates.(6)Two points and in are 6-adjacent if they are 18-adjacent and differ by exactly one coordinate.

Definition 2. Let be a subset of a digital image. A simplicial group in digital images consists of a sequence of groups and collections of group homomorphisms and , , that satisfies the following axioms:

Definition 3. Given a simplicial group with -adjacency, the Moore complex of is the chain complex defined by

with induced from by restriction.

The th homology group of the Moore complex of is

2. Hypercrossed Complex Pairings in Digital Images

First of all we adapt ideas from Carrasco and Cegarra [3–5] to get the construction in digital images. We define a set consisting of pairs of elements from with and , with respect to lexicographic ordering in where and .

Consider the following diagram:

(4)

where

and define and as and . Since a digital image has the additive group structure, define the commutator as

Thus

The normal subgroup of is generated by the elements of the form

where and .

Theorem 4. 2-dimensional normal subgroup with 8-adjacency is generated by the elements of the form

Proof. Let and for . For and ,

Thus and this is the element generating normal subgroups.

Proposition 5. 3-dimensional normal subgroup with 26-adjacency is generated by the elements of the following forms:

(i),(ii),(iii),(iv),(v),(vi).

Proof. For the possible pairings are the following:

(i),(ii),(iii),(iv),(v),(vi).

For all and the corresponding generators of are the following with and for , :

(i)

(ii)

For all and and considering the map , the corresponding generator of is

(iii)

For all , and for the corresponding generators of are

(iv)

(v)

(vı)

Theorem 6. Let be a 2-dimensional Moore complex of a simplicial group . Then where is induced from by restriction.

Proof. For , assume that , , and , . Now calculate .

Since , from Proposition 5

At first we investigate whether is in or not.

therefore .

Secondly we examine whether is in or not.

Since

From the assumption , we get

Theorem 7. Let be a 3-dimensional Moore complex of a simplicial group with 26-adjacency. Then

where is induced from by restriction.

Proof. For investigate where and .

From Proposition 5 we have . Then applying to , we get the following:

Firstly, examine whether is in or not:

So .

Secondly we investigate whether is in or not:

Therefore .

Finally we check whether is in or not.

Since

therefore .

We get

since .

If

then

At first we check whether is in , , and or not.

Thus .

Next, since

and, finally,

Now examine whether is in , , and or not:

Therefore . We have the following:

So .

For all and if

then

Firstly investigate whether is in , , and or not:

Thereby . We have

For this reason . We also have

Hence .

Later on we research whether is in , , and or not.

Since , .

Since , .

Since , .

Thus .

For all , since ,

By using properties of the commutator we have

Thus

If , then

Firstly we check whether is in , , and or not:

Therefore . Since

. We have

Hence .

Because of the case ,

If , then

Consider the following commutator:

and code the terms of this commutator such as

in order to simplify the algebraic operations. Thus, by using the properties and definition of the commutator we obtain the following:

Consider the following cases:

And from the remaining terms we get

Consequently for we have

Corollary 8. Let be a 3-dimensional Moore complex of a simplicial group with 26-adjacency. Then

Proof. Otherwise inclusion for the previous theorem is obtained from [4, 5]. Therefore

3. Conclusion

In this paper for dimension 2 and dimension 3, we obtained the Moore complex of simplicial groups generated by hypercrossed complex pairings in digital images.

References

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P. Carrasco and A. M. Cegarra, “Group-theoretic algebraic models for homotopy types,” Journal of Pure and Applied Algebra, vol. 75, no. 3, pp. 195–235, 1991.

A. Mutlu, Peiffer pairings in the moore complex of a simplicial group [Ph.D. thesis], University of Walles, Bangor, UK, 1997.

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