Fig. 3From: Bi-objective integer programming for RNA secondary structure prediction with pseudoknotsDifferent cases of forbidden base pairs in RNA secondary structures with pseudoknots. a The base i of level p cannot be paired with several bases at the same time, from the same or different level; and the base pair between the bases i and j cannot exist on two different levels p and q at the same time. b Two base pairs ij and i′j′ forming a pseudoknot cannot exist at the same level pBack to article page