Zobrazeno 1 - 10
of 12
pro vyhledávání: '"AKIHIRO SHIKAMA"'
Publikováno v:
Discrete Mathematics. 340:991-994
Let P be an arbitrary finite partially ordered set. It will be proved that the number of edges of the order polytope 풪 ( P ) is equal to that of the chain polytope C ( P ) . Furthermore, it will be shown that the degree sequence of the finite simpl
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::2a4fc13a3dd63a26fa725084f4754023
https://doi.org/10.1016/j.disc.2017.01.005
https://doi.org/10.1016/j.disc.2017.01.005
Autor:
Akihiro Shikama
Publikováno v:
J. Commut. Algebra 10, no. 2 (2018), 265-274
In this paper, we give a toric representation of the associated ring of a polyomino which is obtained by removing a convex polyomino from its ambient rectangle.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3994c5e21fc89b025e1650de6aebc1ac
https://doi.org/10.1216/jca-2018-10-2-265
https://doi.org/10.1216/jca-2018-10-2-265
Publikováno v:
Mathematische Nachrichten. 288:775-783
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::fc97cc905a7ee9aa63b5397b2d26493a
https://doi.org/10.1002/mana.201400153
https://doi.org/10.1002/mana.201400153
Publikováno v:
J. Commut. Algebra 9, no. 3 (2017), 413-422
IntroductionPolyominoes are two dimensional objects which are originally rooted in recre-ational mathematics and combinatorics. They have been widely discussed in con-nection with tiling problems of the plane. Typically, a polyomino is plane figureo
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::86abfe69b3a9b2ac34a0e2bbfd19bf32
https://projecteuclid.org/euclid.jca/1501574429
https://projecteuclid.org/euclid.jca/1501574429
Publikováno v:
Journal of Algebra. 408:138-146
Let G be a finite connected simple graph and I G the toric ideal of the edge ring K [ G ] of G. In the present paper, we study finite graphs G with the property that I G is generated by quadratic binomials and I G possesses no quadratic Grobner basis
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::322f5e77dfdeb7e38c172235fe685dcb
https://doi.org/10.1016/j.jalgebra.2013.09.039
https://doi.org/10.1016/j.jalgebra.2013.09.039
Autor:
Hidefumi Ohsugi, Takuji Hayashi, Ginji Hamano, Akiyoshi Tsuchiya, Takayuki Hibi, Kei Sato, Akihiro Shikama, Koichi Hirayama
Publikováno v:
Homological and Computational Methods in Commutative Algebra ISBN: 9783319619422
The edge polytope of a finite graph is the convex hull of the column vectors of its vertex-edge incidence matrix. In this paper, we discuss the existence of a regular unimodular triangulation of normal edge polytopes of finite graphs. For normal edge
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::9180dc6c95f4007890f41bbcc2bb65d2
https://doi.org/10.1007/978-3-319-61943-9_10
https://doi.org/10.1007/978-3-319-61943-9_10
For a pair [Formula: see text] of finite posets the generators of the ideal [Formula: see text] correspond bijectively to the isotone maps from [Formula: see text] to [Formula: see text]. In this note we determine all pairs [Formula: see text] for wh
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e3db3099597e715166a803ddab616fb2
https://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&origin=inward&scp=84940833670
https://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&origin=inward&scp=84940833670
It is shown that for large classes of posets $P$ and $Q$, the defining ideal $J_{P,Q}$ of an isotonian algebras is generated by squarefree binomials. Within these classes, those posets are classified for which $J_{P,Q}$ is quadratically generated.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::626a5bc9c2c0e5c96c53bf9d3834104d
Autor:
Akihiro Shikama
IntroductionPolyominoes are two dimensional objects which are originally rooted in recre-ational mathematics and combinatorics. They have been widely discussed in con-nection with tiling problems of the plane. Typically, a polyomino is plane figureo
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7488fabc68b7c8bb5e3404e8442583ec
http://arxiv.org/abs/1503.04782
http://arxiv.org/abs/1503.04782
To a pair $P$ and $Q$ of finite posets we attach the toric ring $K[P,Q]$ whose generators are in bijection to the isotone maps from $P$ to $Q$. This class of algebras, called isotonian, are natural generalizations of the so-called Hibi rings. We dete
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d0e3cad003e1d27948c502644b8fcdde