convex up and down Some authors say that a curve is convex up when it is concave down, and convex down when it is concave up (see concavity).
convex up and down
数学辞典收录了4151条数学词条，基本涵盖了常用数学知识及数学英语单词词组的翻译及用法，是数学学习的有利工具。