European Journal of Combinatorics ( IF 1.0 ) Pub Date : 2020-12-22 , DOI: 10.1016/j.ejc.2020.103294 Toufik Mansour , Reza Rastegar
In this paper, we consider various classes of polyiamonds that are animals residing on the triangular lattice. By careful analyses through certain layer-by-layer decompositions and cell pruning/growing arguments, we derive explicit forms for the generating functions of the number of nonempty translation-invariant baryiamonds (bargraphs in the triangular lattice), column-convex polyiamonds, and convex polyiamonds with respect to their perimeter. In particular, we show that the number of
(A) baryiamonds of perimeter are asymptotically where is a root of a certain explicit polynomial of degree 5.
(B) column-convex polyiamonds of perimeter are asymptotic to
(C) convex polyiamonds of perimeter is asymptotic to
中文翻译:
三角格子上各种动物的枚举
在本文中,我们考虑了居住在三角晶格上的动物的各种类别的聚钻石。通过对某些逐层分解和单元修剪/增长参数的仔细分析,我们得出了非空平移不变大麦芽(三角格子中的条形图),圆柱凸多菱形和凸出数量的生成函数的显式形式。 Polyiamonds的周边。特别是,我们表明
(A)周长 渐近地 哪里 是某个次数为5的显式多项式的根。
(B)周长的圆柱凸多边形 渐近
(C)周边的凸多边形 渐近于