“FOR US, TACKLING THE IDEA of time is a way of taking stock of the 1990s,” write Nicolas Bourriaud and Jérôme Sans at the outset of their brief catalogue essay accompanying “Experiencing Duration,” the eighth installment of the Lyon Biennale, which closed on December 30. And perhaps this retrospective tack was to be expected, given that the timing of the show roughly coincided with the duo’s departure from the Palais de Tokyo in Paris this winter. Under their joint directorship, the institution became strongly associated internationally with many artistic practices that emerged during the final