God and John Conway both disagree with you here, Wayne.
But the real lesson here is this: Always read the definitions that the author of the book you're reading uses.
And if you're teaching mathematics below the graduate level, you should realize that when you use a definition in the classroom that's different from the textbook's definition you're just asking for trouble.
On Thu, 02 May 2013 14:48:05 -0600, Wayne Bishop <firstname.lastname@example.org> wrote:
> But he is also right. Although favored in some circles, it is one of > those (rather few) situations where the inclusive definition is not > universal. In fact, I think the majority of us prefer his, exactly 1 > pair of parallel sides. Moreover, convictions border on the religious. > You know, God is on our side whichever side that is. >
- --Lou Talman Department of Mathematical & Computer Sciences Metropolitan State University of Denver