关于星和条的Ramsey数

令和．该文研究了广义Ramsey数n(K1,n1,…,K1,nt, m1K2,…,msK2)．当1≤■≤∑时,得到了它们的精确值;当∑>■时,得到了它们的上 界．     

对Ramsey数Rn(3)和Schur数上界的改进

证明了Rn(3)≤(e-1/6)n!+1对一切n≥4成立,这里Rn(3)代表Ramsey数R(3,…,3)(其中有n个3);进而得出Schur数Sn≤(e-1/6)n!对一切n≥4成立.     

9个经典Ramsey数R(3,t)的新下界

本文研究了经典Ramsey数R(3,t)的下界问题.利用素数阶循环图的性质改进一般阶循环图团数的计算方法,获得了9个经典Ramsey数R(3,t)的新下界:R(3,29)≥183,R(3,30)≥189,R(3,32)≥213,R(3,33)≥218,R(3,34)≥226,R(3,35)≥231,R(3,36)≥239,R(3,37)≥244,R(3,38)≥256,其中前三个结果分别改进了迄今已知的最好的下界,后6个结果是本文首次报道的.     

对于K2+Tm和完全图的Ramsey函数的渐近上界

本文研究了当n趋于无穷大时,关于K2+Tm和完全图Kn的Ramsey数的渐近上界,以及r(K2+Tm,Kn)和r(K1+Tm,Kn)的渐近关系.利用李雨生等人所给出的一个独立数的下界公式,给出了r(K4,Kn)和r(Kk-c,Kn)的渐近上下界,推广了李雨生等人所给出的r(K1+Tm,Kn)的下界.     

一类混合Ramsey数

设a(G)表示图G的点荫度,m为正整数,H为连通图,混合Ramsey数v(a;m;H)被定义的为最小的正整数P,使得对任意P阶图G则有a(G)≥m或者H包括于G^-。本文给出了v(a;m;H)的一种计算方法,并对图Cn和轮Wn确定了v(a;n;Cn)和v(a;m;Wn)的值。     

用Paley图计算对角Ramsey数下界的新方法

本文研究了对角Paley数的下界问题.利用一个新发现的Paley图的自同构,给出了计算Paley图团数的一个新方法,获得了2个对角Rasey数的新下界:R(20,20)≥18877,R(21,21)≥25949.     

ASYMPTOTIC BOUNDS FOR IRREDUNDANT RAMSEY NUMBERS

Abstract

The irredundant Ramsey number s(m,n) is the smallest N such that in every red-blue colouring of the edges of K_N , either the blue graph contains an m-element irredundant set or the red graph contains an n-element irredundant set. We prove an asymptotic lower bound for s(m, n).     

THE BOUNDS ABOUT THE WHEEL-WHEEL RAMSEY NUMBERS

In this paper, we determine the bounds about Ramsey number R(W_m, W_n),where W_i is a graph obtained from a cycle C_i and an additional vertex by joining it to every vertex of the cycle C_i. We prove that 3m+1 ≤ R(W_m, W_n) ≤8m-3 for odd n, m ≥ n ≥ 3, m ≥ 5, and 2m + 1 ≤ R(W_m, W_n) ≤ 7m-2 for even n and m ≥ n + 502. Especially, if m is sufficiently large and n = 3, we have R(W_m, W_3) = 3m + 1.     

SOME RAMSEY THEORY IN BOOLEAN ALGEBRA FOR COMPLEXITY CLASSES

It is known that for two given countable sets of unary relations A and B on ω there exists an infinite set H ? ω on which A and B are the same. This result can be used to generate counterexamples in expressibility theory. We examine the sharpness of this result.     

Ramsey数r（k,l）的新下界公式

本文给出并证明了Ｒａｍｓｅｙ数ｒ（ｋ，ｌ）的一个新下界公式ｒ（ｋ，ｌ）≥１．５（ｋ－１）（ｌ－１），此下界公式与文献［１，２］所给出的下界公式ｒ（ｋ，ｌ）＞（ｎ２＾ｎ／２）／（ｅ√２，ｎ＝ｍｉｎ（ｋ，ｌ）相比，当ｋ，ｌ较小时，或ｋ，ｌ相差较大明要优越。     

A GAME-THEORETIC PROOF OF ANALYTIC RAMSEY THEOREM

We give a simple game-theoretic proof of Silver's theorem that every analytic set is Ramsey. A set P of subsets of ω is called Ramsey if there exists an infinite set H such that either all infinite subsets of H are in P or all out of P. Our proof clarifies a strong connection between the Ramsey property of partitions and the determinacy of infinite games.     

SMALL RAMSEY NUMBERS II: CRITICAL COLOURINGS FOR r(C5 + e,K5)

Abstract

It is shown that if G is a graph of order 16 such that C₅+e ? G and K₅ ? [Gbar] then either 4K₄ ? G or G is one of 5 other graphs.     

COMPUTING THE SPREADING AND COVERING NUMBERS

Let S = k[x ₁,…,x _n ], d a positive integer, and suppose that S _D is the vector space of all polynomials of degree d in S. Define α _n (d) ? max { dim _k V| V monomial subspace of S _d , dim _k S ₁ V = n dim _k V} and ρ _n (d +1) ? min {dim _k V | V monomial subspace of S _d , S ₁ V = S _d+1}. The numbers α _n (d) and ρ _n (d+ 1) are called the spreading numbers and covering numbers, respectively. We describe an approach to calculate these numbers that uses simplicial complexes.     

涉及Euler数、Bernoulli数和推广的第一类Stirling数的一些恒等式

利用递推关系把文［１］、［２］中的有关结论推广到一般情形，建立起涉及Ｅｕ－ｌｅｒ数、Ｂｅｒｎｏｕｌｉ数和推广的第一类Ｓｔｉｒｌｉｎｇ数的一些恒等式．     

WELFARE MEASUREMENT OF TECHNOLOGICAL AND ENVIRONMENTAL EXTERNALITIES IN THE RAMSEY GROWTH MODEL

This paper deals with the measurement of economic welfare within the framework of the Ramsey growth model, when there are anticipated technological and/or environmental changes. It is shown that, under such circumstances, the Hamiltonian along an optimal trajectory underestimates the maximum sustainable utility, meaning that the welfare measure suggested in several recent studies would be incorrect in this case. We also derive the appropriate welfare measure in the presence of technological and environmental changes. The second part of the study concerns the welfare implications of unanticipated technological change.     

n元Euler数和多项式与n元Bernoulli数和多项式

本文给出了ｎ元Ｅｕｌｅｒ数，ｎ元Ｂｅｒｎｏｕｌｌｉ数，ｎ元Ｅｕｌｅｒ多项式，ｎ元Ｂｅｒｎｏｕｌｌｉ多项式的定义，导出了它们的母函数，得到了ｎ元Ｅｕｌｅｒ数与Ｅｕｌｅｒ数ｎ元Ｂｅｒｎｏｕｌｌｉ数与Ｂｅｒｎｏｕｌｌｉ数，ｎ元Ｅｕｌｅｒ多项式与Ｂｅｒｎｏｕｌｌｉ多项式的关系式。     

COMPONENTWISE CONDITION NUMBERS FOR GENERALIZED MATRIX INVERSION AND LINEAR LEAST SQUARES

We present componentwise condition numbers for the problems of Moore-Penrose generalized matrix inversion and linear least squares. Also, the condition numbers for these condition numbers are given.     

截断和大数律的收敛速度

本文研究了截断和大数律的收敛速度，证明了截断和（固定）完全收敛性定理以及大数律收敛速度的几个等价条件，从而推广了独立和的结果。