Rainbow AP(4) in an almost equinumerous coloring ★★

Author(s): Conlon

Problem   Do 4-colorings of $ \mathbb{Z}_{p} $, for $ p $ a large prime, always contain a rainbow $ AP(4) $ if each of the color classes is of size of either $ \lfloor p/4\rfloor $ or $ \lceil p/4\rceil $?

Keywords: arithmetic progression; rainbow

Linear-size circuits for stable $0,1 < 2$ sorting? ★★

Author(s): Regan

Problem   Can $ O(n) $-size circuits compute the function $ f $ on $ \{0,1,2\}^* $ defined inductively by $ f(\lambda) = \lambda $, $ f(0x) = 0f(x) $, $ f(1x) = 1f(x) $, and $ f(2x) = f(x)2 $?

Keywords: Circuits; sorting