A $O(n^2)$ lower bound for swaping the order of $n$ input bits in planar boolean circuit
Author: Bin Tian
ABSTRACT
When confined to a 2 dimensional world, many regular tasks become
supprisingly hard. One example is to swap the order of $n$ input
bits in a planar boolean circuit. Mario Szegedy conjectured that
$O(n^2)$ gates are necessary. This paper gives a short proof.