  Recently, Fulek et al. have presented Hanani-Tutte results for (radial) level
planarity, i.e., a graph is (radial) level planar if it admits a (radial) level
drawing where any two (independent) edges cross an even number of times. We
show that the 2-Sat formulation of level planarity testing due to Randerath et
al. is equivalent to the strong Hanani-Tutte theorem for level planarity.
Further, we show that this relationship carries over to radial level planarity,
which yields a novel polynomial-time algorithm for testing radial level
planarity.
