Balance Theorems for Height-2 Posets

نویسنده

  • W. T. TROTTER
چکیده

We prove that every height-2 finite poset with three or more points has an incomparable pair (.x, J) such that the proportion of all linear extensions of the poset in which s is less than y is between l/3 and 213. A related result of Koml6s says that the containment interval [l/3,2/3] shrinks to [l/2, l/2] in the limit as the width of height-2 posets becomes large. We conjecture that a poset denoted by V,’ maximizes the containment interval for height-2 posets of width m + 1. Mathematics Subject Classification (1991). 06A07.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Minors and Dimension

It has been known for 30 years that posets with bounded height and with cover graphs of bounded maximum degree have bounded dimension. Recently, Streib and Trotter proved that dimension is bounded for posets with bounded height and planar cover graphs, and Joret et al. proved that dimension is bounded for posets with bounded height and with cover graphs of bounded tree-width. In this paper, it ...

متن کامل

Morita theorems for partially ordered monoids

Two partially ordered monoids S and T are called Morita equivalent if the categories of right S-posets and right T -posets are Pos-equivalent as categories enriched over the category Pos of posets. We give a description of Pos-prodense biposets and prove Morita theorems I, II, and III for partially ordered monoids.

متن کامل

JOURNAL OF THE EGYPTIAN MATHEMATICAL SOCIETY (J. Egypt. Math. Soc.)Vol.14(1)(2006)pp5-13 Recognition

The paper contains a recognition algorithmic method for deciding whether a given poset, P , is prime. The algorithm is designed to determine whether there exists a proper P -autonomous set including specified two distinct elements of P . The steps are repeated for all ordered pairs of distinct elements of P , if it is prime, in a polynomial time. As an application of this test, the author count...

متن کامل

Definition of Flat Poset and Existence Theorems for Recursive

Reduction Systems and Idea of Knuth-Bendix Completion Algorithm By Grzegorz Bancerek . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Double Series and Sums By Noboru Endou . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Dual Spaces and Hahn-Banach Theorem By Keiko Narita, Noboru Endou, and Yasunari Shidama 69 Semiring of Sets By Roland Coghetto . ...

متن کامل

Irreducible Posets with Large Height Exist

The dimension of a poset (X, P) is the minimum number of linear extensions of P whose intersection is P. A poset is irreducible if the removal of any point lowers the dimension. If A is an antichain in X and X A # B’, then dim X < 2 width (X A) + 1. We construct examples to show that this inequality is best possible; these examples prove the existence of irreducible posets of arbitrarily large ...

متن کامل

ذخیره 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 نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2004