MathDB
0772

Source:

July 7, 2008
analytic geometryfunctionnumber theoryrelatively prime

Problem Statement

Prove that the set of all the points with both coordinates begin rational numbers can be written as a reunion of two disjoint sets A A and B B such that any line that that is parallel with Ox Ox, and respectively Oy Oy intersects A A, and respectively B B in a finite number of points.