• Title/Summary/Keyword: posets

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DISCONNECTED POSETS AND LD-IRREDUCIBLE POSETS

  • Chae, Gab-Byung;Cheong, MinSeok;Kim, Sang-Mok
    • Communications of the Korean Mathematical Society
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    • v.36 no.1
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    • pp.189-196
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    • 2021
  • Using ld-irreducible posets, we can easily characterize posets with respect to linear discrepancy. However, it is difficult to have the list of all the irreducible posets with respect to a given linear discrepancy. In this paper, we investigate some properties of disconnected posets and connected posets with respect to linear discrepancy, respectively and then we find various relationships between ld-irreducibily and connectedness. From these results, we suggest some methods to construct ld-irreducible posets.

A CHARACTERIZATION OF n-POSETS OF LD n - k WITH SIMPLE POSETS

  • Chae, Gab-Byung;Cheong, Minseok;Kim, Sang-Mok
    • Bulletin of the Korean Mathematical Society
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    • v.55 no.3
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    • pp.777-788
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    • 2018
  • A simple poset is a poset whose linear discrepancy increases if any relation of the poset is removed. In this paper, we investigate more important properties of simple posets such as its width and height which help to construct concrete simple poset of linear discrepancy l. The simplicity of a poset is similar to the ld-irreducibility of a poset. Hence, we investigate which posets are both simple and ld-irreducible. Using these properties, we characterize n-posets of linear discrepancy n - k for k = 2, 3, and, lastly, we also characterize a poset of linear discrepancy 3 with simple posets and ld-irreducible posets.

LINEAR EXTENSIONS OF DIAMOND POSETS

  • Ju, Hyeong-Kwan;Seo, Seunghyun
    • Honam Mathematical Journal
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    • v.41 no.4
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    • pp.863-870
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    • 2019
  • In this paper, we obtain the enumeration results on the number of linear extensions of diamond posets. We find the recurrence relations and exponential generating functions for the number of linear extensions of diamond posets. We also get some results for the volume of graph polytope associated with bipartite graphs which are underlying graphs of diamond posets.

zJ-Ideals and Strongly Prime Ideals in Posets

  • John, Catherine Grace;Elavarasan, Balasubramanian
    • Kyungpook Mathematical Journal
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    • v.57 no.3
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    • pp.385-391
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    • 2017
  • In this paper, we study the notion of $z^J$ - ideals of posets and explore the various properties of $z^J$-ideals in posets. The relations between topological space on Sspec(P), the set $I_Q=\{x{\in}P:L(x,y){\subseteq}I\text{ for some }y{\in}P{\backslash}Q\}$ for an ideal I and a strongly prime ideal Q of P and $z^J$-ideals are discussed in poset P.

Numerical measures of Indicating Placement of Posets on Scale from Chains to Antichains

  • Bae, Kyoung-Yul
    • The Journal of Information Technology and Database
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    • v.3 no.1
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    • pp.97-108
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    • 1996
  • In this paper we obtain several function defined on finite partially ordered sets(posets) which may indicate constraints of comparability on sets of teams(tasks, etc.) for which evaluation is computationally simple, a relatively rare condition in graph-based algorithms. Using these functions a set of numerical coefficients and associated distributions obtained from a computer simulation of certain families of random graphs is determined. From this information estimates may be made as to the actual linearity of complicated posets. Applications of these ideas is to all areas where obtaining rankings from partial information in rational ways is relevant as in, e.g., team_, scaling_, and scheduling theory as well as in theoretical computer science. Theoretical consideration of special and desirable properties of various functions is provided permitting judgment concerning sensitivity of these functions to changes in parameters describing (finite) posets.

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THE JUMP NUMBER OF BIPARTITE POSETS FROM MATROIDS

  • Jung, Hyung-Chan;Yoon, Young-Jin
    • Journal of the Korean Mathematical Society
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    • v.33 no.3
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    • pp.679-684
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    • 1996
  • In this paper we try to investigate the connection between matroids and jump numbers. A couole of papers [3, 5] are known, but they discuss optimization problems with matroid structure. Here we calculate the jump numbers of some bipartite posets which are induced by matroids.

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THE LINEAR DISCREPANCY OF A PRODUCT OF TWO POSETS

  • Cheong, Minseok
    • Bulletin of the Korean Mathematical Society
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    • v.54 no.3
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    • pp.1081-1094
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    • 2017
  • For a poset $P=(X,{\leq}_P)$, the linear discrepancy of P is the minimum value of maximal differences of all incomparable elements for all possible labelings. In this paper, we find a lower bound and an upper bound of the linear discrepancy of a product of two posets. In order to give a lower bound, we use the known result, $ld({\mathbf{m}}{\times}{\mathbf{n}})={\lceil}{\frac{mn}{2}}{\rceil}-2$. Next, we use Dilworth's chain decomposition to obtain an upper bound of the linear discrepancy of a product of a poset and a chain. Finally, we give an example touching this upper bound.