5 citations · 17 across the 13 of their papers we have counts for
13 papers
On the relations of isotonian algebras
Jürgen Herzog, Ayesha Asloob Qureshi, Akihiro Shikama
It is shown that for large classes of posets and , the defining ideal of an isotonian algebras is generated by squarefree binomials. Within these classes, those po…
Toric representations of algebras defined by certain nonsimple polyominoes
Akihiro Shikama
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.
Isotonian Algebras
Mina Bigdeli, Jürgen Herzog, Takayuki Hibi +2
To a pair and of finite posets we attach the toric ring whose generators are in bijection to the isotone maps from to . This class of algebras, called isoto…
Multibasic Ehrhart theory
Aki Mori, Takeshi Morita, Akihiro Shikama
In the present paper, we introduce a multibasic extension of the Ehrhart theory. We give a multibasic extension of Ehrhart polynomials and Ehrhart series. We also show that an anal…
The numbers of edges of the order polytope and the chain poyltope of a finite partially ordered set
Takayuki Hibi, Nan Li, Yoshimi Sahara +1
Let be an arbitrary finite partially ordered set. It will be proved that the number of edges of the order polytope is equal to that of the chain polytope ${\m…
Alexander duality for monomial ideals associated with isotone maps between posets
Juergen Herzog, Ayesha Asloob Qureshi, Akihiro Shikama
For a pair of finite posets the generators of the ideal correspond bijectively to the isotone maps from to . In this note we determine all pairs for…
Toric rings of nonsimple polyominoes
Akihiro Shikama
It is known that toric ring of a simple polyomino is ring homomorphic to a edge ring of a weakly chordal bipartite graph. In this paper we identify the toric ring of nonsimple poly…
Simple Polyominoes are Prime
Ayesha Asloob Qureshi, Takafumi Shibuta, Akihiro Shikama
In this paper we show that polyomino ideal of a simple polyomino coincides with the toric ideal of a weakly chordal bipartite graph and hence it has a quadratic Gröbner basis with…
Decomposable edge polytopes of finite graphs
Atsushi Funato, Nan Li, Akihiro Shikama
Edge polytopes is a class of interesting polytope with rich algebraic and combinatorial properties, which was introduced by Ohsugi and Hibi. In this papar, we follow a previous stu…
Gröbner bases of balanced polyominoes
Jürgen Herzog, Ayesha Asloob Qureshi, Akihiro Shikama
We introduce balanced polyominoes and show that their ideal of inner minors is a prime ideal and has a quadratic Gröbner basis with respect to any monomial order, and we show that…
A Koszul filtration for the second squarefree Veronese subring
Takayuki Hibi, Ayesha Asloob Qureshi, Akihiro Shikama
The second squarefree Veronese subring in variables is the edge ring of the complete graph with vertices. It is proved that every second squarefree Veronese subring possess…
The number of edges of the edge polytope of a finite simple graph
Takayuki Hibi, Aki Mori, Hidefumi Ohsugi +1
Let be an integer. It is known that the number of edges of the edge polytope of the complete graph with vertices is . In this paper, we study the maxi…
Many toric ideals generated by quadratic binomials possess no quadratic Gröbner bases
Takayuki Hibi, Kenta Nishiyama, Hidefumi Ohsugi +1
Let be a finite connected simple graph and the toric ideal of the edge ring of . In the present paper, we study finite graphs with the property that $I_{G…