关于江泽坚等著《实变函数论》的一个小瑕疵

A Small Flaw in “Real Variable Function Theory” Written by Jiang Ze-jian et al

指出江泽坚等合编教材《实变函数论》[2-3]中的一处瑕疵.这个瑕疵起始于第二版,在第三版时又没更正,时间已有22年(1994-2016).鉴于此教材影响大,使用面广,我们特写此注记将此瑕疵指出,与作者和读者商榷.

This paper points out a flaw in ＂Real Variable Function Theory＂ （Second edition and Third edition） written by Jiang Ze-jian et al. This flaw started in the second edition, and did not correct in the third edition, which lasted for more than 20 years（1994--2016）. In view of the fact tha;his textbook has great influence and is widely used, we write this note to point out the flaw, and discuss with the author and the reader.