A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2018; you can also visit the original URL.
The file type is
We prove that any subset of M2 that intersects no line in more than two points either is zero-dimensional or contains an arc. This is used to prove that any subset of R2 that intersects each line in exactly two points is zero-dimensional, answering a question of Mauldin.doi:10.1090/s0002-9939-1992-1093599-1 fatcat:l6ql5za5fvbtbdv4ilusbwg4ke