A theorem of Erdos states:

"There exists an absolute constant c such that, if n>ck, and if a₁/b₁, a₂/b₂, ... are the Farey fractions of order n, then a_x/b_x and a_x+kb_x+k are similarly ordered."

Can someone provide a definition of "similarly ordered" as used here?

Thanks for any insight.

Cheers, Scott