Enumeration of symmetry classes of convex polyominoes on the honeycomb lattice
نویسندگان
چکیده
Hexagonal polyominoes are polyominoes on the honeycomb lattice. We enumerate the symmetry classes of convex hexagonal polyominoes. Here convexity is to be understood as convexity along the three main column directions. We deduce the generating series of free (i.e. up to reflection and rotation) and of asymmetric convex hexagonal polyominoes, according to area and half-perimeter. We give explicit formulas or implicit functional equations for the generating series, which are convenient for computer algebra.
منابع مشابه
0 M ar 2 00 4 Enumeration of Symmetry Classes of Convex Polyominoes on the Honeycomb Lattice ∗
Hexagonal polyominoes are polyominoes on the honeycomb lattice. We enumerate the symmetry classes of convex hexagonal polyominoes. Here convexity is to be understood as convexity along the three main column directions. We deduce the generating series of free (i.e. up to reflection and rotation) and of asymmetric convex hexagonal polyominoes, according to area and half-perimeter. We give explici...
متن کاملEnumeration of Symmetry Classes of Convex Polyominoes in the Square Lattice
This paper concerns the enumeration of rotation-type and congruence-type convex polyominoes on the square lattice. These can be defined as orbits of the groups C4, of rotations, and D4, of symmetries, of the square, acting on (translation-type) polyominoes. In virtue of Burnside’s Lemma, it is sufficient to enumerate the various symmetry classes (fixed points) of polyominoes defined by the elem...
متن کاملOn the Generation and Enumeration of some Classes of Convex Polyominoes
ECO is a method for the recursive generation, and thereby also the enumeration of classes of combinatorial objects. It has already found successful application in recent literature both to the exhaustive generation and to the uniform random generation of various objects classified according to several parameters of interest, as well as to their enumeration. In this paper we extend this approach...
متن کاملA Bijection for Directed-Convex Polyominoes
In this paper we consider two classes of lattice paths on the plane which use north, east, south, and west unitary steps, beginning and ending at 0 0 . We enumerate them according to the number of steps by means of bijective arguments; in particular, we apply the cycle lemma. Then, using these results, we provide a bijective proof for the number of directed-convex polyominoes having a fixed num...
متن کاملEnumeration of convex polyominoes using the ECO method
ECO is a method for the enumeration of classes of combinatorial objects based on recursive constructions of such classes. In the first part of this paper we present a construction for the class of convex polyominoes based on the ECO method. Then we translate this construction into a succession rule. The final goal of the paper is to determine the generating function of convex polyominoes accord...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Theor. Comput. Sci.
دوره 346 شماره
صفحات -
تاریخ انتشار 2005