Bridge index for theta curves in the 3-sphere
The author generalizes the notion of bridge presentation, bridge index, thin position and primeness to theta curves which are graphs in 3-sphere consisting of two vertices and three edges. A result of \textit{A. Thompson} [Topology 36, No. 2, 505-507 (1997; Zbl 0867.57009)] will be generalized in the article stating that under certain conditions thin position of a theta curve coincides with the bridge presentation related to the bridge index of the theta curve. It is shown that theta curves with bridge index 2 are prime.
scientific article; zbMATH DE number 1067517
scientific article