去年深秋,我与赵毅衡、刘旭光等许多学界朋友在南京的一次学术会议上见面。会上热烈的讨论,激发了兴致,也打开了思路。记得好像毅衡兄提出了一个话题,我也作了回应。当时相约,把谈的内容写下来,找一个地方发表。回到北京后,就像人生中许多的经验一样,过去的就过去了,只留下关于愉快经验的记忆。最近旭光一再催促,并寄来了一些文 Late last year, I met with many academic friends like Zhao Yiheng and Liu Xuguang at an academic conference in Nanjing. At the meeting of the heated discussion, inspired the interest, but also opened up ideas. I remember as if Yi Hengxiong raised a topic, I also responded. At that time similar to write down the content to find a place to publish. After returning to Beijing, like many experiences in life, the past is passed away, leaving only memories of pleasant experiences. Recently Xuguang repeatedly urging, and sent some text