Hereditary Discrepancies in Different Numbers of Colors II
  We bound the hereditary discrepancy of a hypergraph $\HH$ in two colors in terms of its hereditary discrepancy in $c$ colors. We show that $\herdisc(\HH,2) \le K c \herdisc(\HH,c)$, where $K$ is some absolute constant. This bound is sharp. 
Benjamin Doerr, Mahmoud Fouz