如何评价J.Keisler？
在国际数学界，去年有一项重大发现。这项发现是依据J.Keisler关于模型论（复杂性）的研究成果做出的。据此，去年7月，相关研究人员获得集合论领域的最高奖项“豪斯多夫”（Hausdorff）大奖。
实际上，Keisler撰写的无穷小微积分教材就是模型论的创新，也应该得微积分教育改革的大奖。
袁萌 6月30日
附：
Mathematicians Measure Infinities and Find They’re Equal
（此文发表于2017.9.1）
……H.Jerome Keisler invented “Keisler’s order.”
Courtesy of H. Jerome Keisler
For a model theorist, a “theory” is the setof axioms, or rules, that define an area of mathematics. You can think of modeltheory as a way to classify mathematical theories — an exploration of thesource code of mathematics. “I think the reason people are interested inclassifying theories is they want to understand what is really causing certainthings to happen in very different areas of mathematics,” said H. JeromeKeisler, emeritus professor of mathematics at the University of Wisconsin,Madison.
It isn’t always obvious what it means for a theoryto be complex. Much work in the field is motivated in part by a desire tounderstand that question. Keisler describes complexity as the range of thingsthat can happen in a theory — and theories where more things can happen aremore complex than theories where fewer things can happen.。。。。。。（省略）
