> Hello. While I was doing research on the equichordal point problem, > I encountered a confusion.
I might be able to clear it up, since I've been interested in this problem for more than 40 years, and know the state of play. I'll read on...
> Equichordal Point Problem: Can a plane region have two equichordal > points?
The answer is definitely "No", as was first established by Rychlik about 5 years ago. I read on again...
> The source of the confusion is Mathworld. On the one hand, it states > that the problem was fully solved by Rychlik in 1997
So that's the right one, while in this one:
> on the other hand, it states that "a plane convex region can > have two equichordal points."
the word "can" is obviously a typographical error for "cannot".
This particular error ("can" for "cannot") is really quite common. There have been 5 or 6 different instances that have puzzled me for quite considerable times!
> By the way, the problem was solved in the negative: This problem has > been fully solved in the negative by the author of this announcement > just recently. (From abstract of the original paper) i.e., > > No Jordan curve may contain two or more equichordal points. > > Could anyone help me?
You seem to have helped yourself pretty well, but might like to have the reassurance that your guess is the right one.