Every planar graph is known to be acyclically 7-choosable and is conjectured to be acyclically 5-choosable (Borodin et al., 2002). This conjecture if proved would imply both Borodin’s acyclic 5-color theorem (1979) and Thomassen’s 5-choosability theorem (
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机译：已知每个平面图都是非循环的7选择的，并且可以推测是非循环的5选择的（Borodin et al。，2002）。如果证明这一猜想，则将暗示Borodin的无环5色定理（1979）和Thomassen的5选择性定理（
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