This is part of the Biennial Artist Project, a series on the stars of the biennial circuit. You can also read profiles of the top 17 artists and a report on the economics of being a biennial star. The full list of biennial artists (and which galleries represent them) is available to Artnet News Pro members.    Looking at the list of artists who have appeared most often in global art biennials since the last Documenta, in 2017, it becomes clear the extent to which the Biennial World functions as its own, freestanding universe. It has its own concerns, and its own star system. The names that dominate Biennial World…