Flash vertexing algorithms for trigger applications

Flash-algorithm vertex-reconstruction routines can increase speed by a few orders of magnitude over iterative routines and allow the design of dedicated triggers for b- and charm-physics. The idea behind the algorithms is to perform fits analytically for straight tracks, and then add a correction corresponding to OIIIOIII helix local expansions of the tracks. From the point of view of the resolution this is satisfactory for all current HEP experiments.