eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2018-09-01
6
1
1
12
10.22044/jas.2017.6012.1301
1251
MAXIMAL PRYM VARIETY AND MAXIMAL MORPHISM
M. Farhadi Sangdehi
farhadi@du.ac.ir
1
departement of math and computer science Damghan University
We investigated maximal Prym varieties on finite fields by attaining their upper bounds on the number of rational points. This concept gave us a motivation for defining a generalized definition of maximal curves i.e. maximal morphisms. By MAGMA, we give some non-trivial examples of maximal morphisms that results in non-trivial examples of maximal Prym varieties.
http://jas.shahroodut.ac.ir/article_1251_754f567f47608f98c2a43186b7dde0ee.pdf
Prym Variety
Maximal Curve
Maximal Morphism
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2018-09-01
6
1
13
28
10.22044/jas.2017.5482.1278
1252
SIGNED GENERALIZED PETERSEN GRAPH AND ITS CHARACTERISTIC POLYNOMIAL
E. Ghasemian
e.ghasemian@yahoo.com
1
Gh. H. Fath-Tabar
fathtabar@kashanu.ac.ir
2
Department of Pure Mathematics, Faculty of Mathematical Sciences, University of Kashan, Kashan 87317-53153, I. R. Iran.
Department of Pure Mathematics, Faculty of Mathematical Sciences, University of Kashan, Kashan 87317-53153, I. R. Iran.
Let G^s be a signed graph, where G = (V;E) is the underlying simple graph and s : E(G) to {+, -} is the sign function on E(G). In this paper, we obtain k-th signed spectral moment and k-th signed Laplacian spectral moment of Gs together with coefﬁcients of their signed characteristic polynomial and signed Laplacian characteristic polynomial are calculated.
http://jas.shahroodut.ac.ir/article_1252_6c32e6bd4ccfe3ab6aa2450e8fa4c181.pdf
Singed graph
Signed Petersen graph
Adjacency matrix
Signed Laplacian matrix
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2018-09-01
6
1
29
42
10.22044/jas.2018.5530.1280
1253
IDEALS WITH (d1, . . . , dm)-LINEAR QUOTIENTS
L. Sharifan
leilasharifan@gmail.com
1
Department of Mathematics and Computer Sciences, Hakim Sabzevari University, Sabzevar, Iran and School of Mathematics, Institute for research in Fundamental Sciences (IPM), P.O. Box: 19395-5746, Tehran, Iran.
In this paper, we introduce the class of ideals with $(d_1,ldots,d_m)$-linear quotients generalizing the class of ideals with linear quotients. Under suitable conditions we control the numerical invariants of a minimal free resolution of ideals with $(d_1,ldots,d_m)$-linear quotients. In particular we show that their first module of syzygies is a componentwise linear module.
http://jas.shahroodut.ac.ir/article_1253_6f8ef72f643795159174715408d317ee.pdf
Mapping cone
componentwise linear module
regularity
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2018-09-01
6
1
43
57
10.22044/jas.2018.6259.1311
1254
ON MAXIMAL IDEALS OF R∞L
A. A. Estaji
aaestaji@gmail.com
1
A. Mahmoudi Darghadam
m.darghadam@yahoo.com
2
Faculty of Mathematics and Computer Sciences, Hakim Sabzevari University, Sabzevar, Iran. Email: aaestaji@hsu.ac.ir and aaestaji@gmail.com
Faculty of Mathematics and Computer Sciences, Hakim Sabzevari University, Sabzevar, Iran. Email: m.darghadam@yahoo.com
Let $L$ be a completely regular frame and $mathcal{R}L$ be the ring of real-valued continuous functions on $L$. We consider the set $$mathcal{R}_{infty}L = {varphi in mathcal{R} L : uparrow varphi( dfrac{-1}{n}, dfrac{1}{n}) mbox{ is a compact frame for any $n in mathbb{N}$}}.$$ Suppose that $C_{infty} (X)$ is the family of all functions $f in C(X)$ for which the set ${x in X: |f(x)|geq dfrac{1}{n} }$ is compact, for every $n in mathbb{N}$. Kohls has shown that $C_{infty} (X)$ is precisely the intersection of all the free maximal ideals of $C^{*}(X)$. The aim of this paper is to extend this result to the real continuous functions on a frame and hence we show that $mathcal{R}_{infty}L$ is precisely the intersection of all the free maximal ideals of $mathcal R^{*}L$. This result is used to characterize the maximal ideals in $mathcal{R}_{infty}L$.
http://jas.shahroodut.ac.ir/article_1254_45a4703f3fc3297b882c27efeed5d7db.pdf
Frame
Compact
Maximal ideal
Ring of real valued continuous functions
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2018-09-01
6
1
59
70
10.22044/jas.2018.5360.1273
1255
THE LATTICE OF CONGRUENCES ON A TERNARY SEMIGROUP
N. Ashrafi
nashrafi@semnan.ac.ir
1
Z. Yazdanmehr
zhyazdanmehr@gmail.com
2
Faculty of Mathematics, Statistics and Computer Science, Semnan University, Semnan, Iran. Email: nashrafi@semnan.ac.ir
Faculty of Mathematics, Statistics and Computer Science, Semnan University, Semnan, Iran. Email: zhyazdanmehr@gmail.com
In this paper we investigate some properties of congruences on ternary semigroups. We also deﬁne the notion of congruence on a ternary semigroup generated by a relation and we determine the method of obtaining a congruence on a ternary semigroup T from a relation R on T. Furthermore we study the lattice of congruences on a ternary semigroup and we show that this lattice is not generally modular, it is not even semimodular. Then we indicate some conditions under which this lattice is modular.
http://jas.shahroodut.ac.ir/article_1255_585b8d0ca4e05982b434b1a9d2ab912e.pdf
Ternary semigroup
congruence
Lattice
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2018-09-01
6
1
71
80
10.22044/jas.2018.6328.1316
1256
ON THE CHARACTERISTIC DEGREE OF FINITE GROUPS
Z. Sepehrizadeh
zohreh.sepehri@gmail.com
1
M. R. Rismanchian
rismanchian133@gmail.com
2
Department of Pure Mathematics, Shahrekord University , P.O.Box 115, Shahrekord, Iran. Email: zohreh.sepehri@gmail.com
Department of Pure Mathematics, Shahrekord University , P.O.Box 115, Shahrekord, Iran. Email: rismanchian133@gmail.com, rismanchian@sku.ac.ir
In this article we introduce and study the concept of characteristic degree of a subgroup in a finite group. We define the characteristic degree of a subgroup H in a finite group G as the ratio of the number of all pairs (h,α) ∈ H×Aut(G) such that h^α∈H, by the order of H × Aut(G), where Aut(G) is the automorphisms group of G. This quantity measures the probability that H can be characteristic in G. We determine the upper and lower bounds for this probability. We also obtain a special lower bound, when H is a cyclic p-subgroup of G.
http://jas.shahroodut.ac.ir/article_1256_9cb3d15cf6327aa4481ad9fb54223403.pdf
Autocommutativity degree
Characteristic degree
p-group