LIKE SO MUCH ART of the present, the work of Sung Tieu necessitates a fair amount of explanatory text. Reading the growing body of writing about Tieu (the artist will open her first US solo exhibitions “Infra-Specter” at Brooklyn’s Amant on March 30, “Civic Floor” at Cambridge’s MIT List Visual Arts Center on April 4 nearly concurrently), I was struck by the frequency with which the Cold War surfaced as a referent. The term rightly identifies the period about which much of the artist’s research is conducted, but also slyly tethers her object of study to her own artistic operations. The Cold War