Removing Independently Even Crossings
Michael J. Pelsmajer, Marcus Schaefer, Daniel Štefankovič · SIAM Journal on Discrete Mathematics · 2010
We show that $\mathrm{cr}(G)\leq({2\,\mathrm{iocr}(G)\atop2})$, settling an open problem of Pach and Tóth [Geombinatorics, 9 (2000), pp. 194–207]. Moreover, $\mathrm{iocr}(G)=\mathrm{cr}(G)$ if $\mathrm{iocr}(G)\leq2$.