德登动物群的发现及其意义

本文通过对德登动物群的研究,确定其时限为中更新世。这一发现弥补了川西高原中更新世无断代化石的空白。并对川西高原西部第四纪河谷阶地的划分,进行了初步的探讨。

Systems of equations for van der Waerden numbers

In this paper we transfer the van der Waerden problem into a problem of solving special systems of equations and give some properties of the solutions for the systems.