Zero to Infinity: Arte Povera 1962-1972 is a “must see” for any serious artist or student of conceptual practices in contemporary art. The Italian Arte Povera movement has been almost invisible in the United States, but comes nicely into focus in this show. It’s clear that it set the stage for the conceptual artists of the 1970s. You can see what Bay Area artists did on that stage while you’re in the neighborhood, with a stop at the new Pasadena Museum of California Art for the spotty but worthwhile On-Ramps: Transitional Moments in California Art. The “Bay Area Conceptual Art of the 1970s” section of the show includes work by Paul Kos and Lynn Hershman, among others.