# Bulletin of the Korean Mathematical Society (B KOREAN MATH SOC )

Publisher: Taehan Suhakhoe

## Description

- Impact factor0.39Show impact factor historyImpact factorYear
- 5-year impact0.37
- Cited half-life5.40
- Immediacy index0.07
- Eigenfactor0.00
- Article influence0.20
- Other titlesBulletin of the Korean Mathematical Society, Bulletin of the Korean Mathematical Society
- ISSN1015-8634
- OCLC6653234
- Material typePeriodical
- Document typeJournal / Magazine / Newspaper

## Publications in this journal

- [Show abstract] [Hide abstract]

**ABSTRACT:**A tournament T is an orientation of a complete graph and an arc in T is called pancyclic if it is contained in a cycle of length l for all 3 <= l <= n, where n is the cardinality of the vertex set of T. In 1994, Moon introduced the graph parameter h(T) as the maximum number of pancyclic arcs contained in the same Hamiltonian cycle of T and showed that h(T) >= 3 for all strong tournaments with n >= 3. Havet later conjectured that h(T) >= 2k +1 for all k-strong tournaments and proved the case k = 2. In 2005, Yeo gave the lower bound h(T) >=(k+5)/2 for all k-strong tournaments T. In this note, we will improve his bound to h(T) >= (2k+7)/3 .Bulletin of the Korean Mathematical Society 11/2014; 51(6):1649-1654. - [Show abstract] [Hide abstract]

**ABSTRACT:**Suppose that G is a finite group and H is a subgroup of G. H is said to be an ss-quasinormal subgroup of G if there is a subgroup B of G such that G=HB and H permutes with every Sylow subgroup of B; H is said to be semi-p-cover-avoiding in G if there is a chief series 1=G 0 <G 1 <⋯<G t =G of G such that, for every i=1,2,...,t, if G i /G i-1 is a p-chief factor, then H either covers or avoids G i /G i-1 . We give the structure of a finite group G in which some subgroups of G with prime-power order are either semi-p-cover-avoiding or ss-quasinormal in G. Some known results are generalized.Bulletin of the Korean Mathematical Society 07/2014; 51(4). - [Show abstract] [Hide abstract]

**ABSTRACT:**We construct new binary optimal self-dual codes of length 50. We develop a construction method for binary self-dual codes with a fixed-point-free automorphism of order 2. Using this method, we find new binary optimal self-dual codes of length 52. From these codes, we obtain Lee-optimal self-dual codes over the ring 𝔽 2 +u𝔽 2 of lengths 25 and 26.Bulletin of the Korean Mathematical Society 07/2014; 51(4). - [Show abstract] [Hide abstract]

**ABSTRACT:**In this paper, we study the structure of m-quasi Einstein manifolds when there exists another distinct solution to the (λ,n+m)-Einstein equation. In particular, we derive sufficient conditions for the non-existence of such solutions.Bulletin of the Korean Mathematical Society 07/2014; 51(4). - [Show abstract] [Hide abstract]

**ABSTRACT:**In this paper, we prove that there is no branch point in the Lorentz space (M,d) obtained as the limit space of a sequence {(M α ,d α )} of compact globally hyperbolic interpolating space-times with C α ± -properties and curvature bounded below. Using this, we also obtain that every maximal time-like geodesic in the limit space (M,d) can be expressed as the limit curve of a sequence of maximal time-like geodesics in {(M α ,d α )}. Finally, we show that the limit space (M,d) satisfies a time-like triangle comparison property which is analogous to the case of Alexandrov curvature bounds in length spaces.Bulletin of the Korean Mathematical Society 07/2014; 51(4). - [Show abstract] [Hide abstract]

**ABSTRACT:**We give analogous criterion to admit a real parabolic connection on real parabolic bundles over a real curve. As an application of this criterion, if real curve has a real point, then we proved that a real vector bundle E of rank r and degree d with gcd (r,d)=1 is real indecomposable if and only if it admits a real logarithmic connection singular exactly over one point with residue given as multiplication by -fracdr. We also give an equivalent condition for real indecomposable vector bundle in the case when real curve has no real points.Bulletin of the Korean Mathematical Society 07/2014; 51(4). - [Show abstract] [Hide abstract]

**ABSTRACT:**Let O n and PO n denote the order-preserving transformation and the partial order-preserving transformation semigroups on the set X n ={1,...,n}, respectively. Then the ‘strictly partial order-preserving transformation semigroup’ SPO n on the set X n , under its natural order, is defined by SPO n =PO n ∖O n . In this paper we find necessary and sufficient conditions for any subset of SPO(n,r) to be a (minimal) generating set of SPO(n,r) for 2≤r≤n-1.Bulletin of the Korean Mathematical Society 07/2014; 51(4). - [Show abstract] [Hide abstract]

**ABSTRACT:**A finite group G is called a SB-group if every subgroup of G is either s-quasinormal or abnormal in G. In this paper, we give a complete classification of those groups which are not SB-groups but all of whose proper subgroups are SB-groups.Bulletin of the Korean Mathematical Society 07/2014; 51(4). - [Show abstract] [Hide abstract]

**ABSTRACT:**Let G be a finite group. The commuting graph Δ(G) of G is a graph whose vertex set is G and two vertices x and y are adjacent if and only if x≠y and xy=yx. In this paper, the authors study the automorphism group of the graph Δ(G). It is proved that Aut(Δ(G)) is abelian or primary if and only if |G|≤2, and Aut(Δ(G)) is asquare-free if and only if |G|≤3. Some new graphs that are useful in studying the group Aut(Δ(G)) are presented and their main properties are investigated.Bulletin of the Korean Mathematical Society 07/2014; 51(4).

Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.