10 citations · 31 across the 16 of their papers we have counts for
6 papers · 1 filter
Strong Lefschetz property of the Kirchhoff algebra of the complete tripartite graph
Yohji Akama
By Whitney's 2-isomorphism theorem, the cycle matroids of two graphs are isomorphic if and only if one graph can be transformed into the other by finitely many applications of two…
Graphs on surfaces with positive Forman curvature or corner curvature
Yohji Akama, Bobo Hua, Yanhui Su +1
On one hand, we study the class of graphs on surfaces, satisfying tessellation properties, with positive Forman curvature on each edge. Via medial graphs, we provide a new proof fo…
A curvature notion for planar graphs stable under planar duality
Yohji Akama, Bobo Hua, Yanhui Su +1
Woess \cite{Woess98} introduced a curvature notion on the set of edges of a planar graph, called -curvature in our paper, which is stable under the planar duality. We study geom…
Tilings of the Sphere by Congruent Pentagons III: Edge Combination
Yohji Akama, Erxiao Wang, Min Yan
There are exactly eight edge-to-edge tilings of the sphere by congruent equilateral pentagons: three pentagonal subdivision tilings with 12, 24, 60 tiles; four earth map tilings wi…
A new order theory of set systems and better quasi-orderings
Yohji Akama
By reformulating a learning process of a set system L as a game between Teacher (presenter of data) and Learner (updater of the abstract independent set), we define the order type…
VC dimension of ellipsoids
Yohji Akama, Kei Irie
We will establish that the VC dimension of the class of d-dimensional ellipsoids is (d^2+3d)/2, and that maximum likelihood estimate with N-component d-dimensional Gaussian mixture…