MathDB

Consider

n

lines in the plane in general position, that is, there are not three of the

n

lines that pass through the same point. Determine if it is possible to label the

k

points where these lines are inserted with the numbers

1

through

k

(using each number exactly once), so that on each line, the labels of the

n-1

points of that line are arranged in increasing order (in one of the two directions in which they can be traversed).

3