<i>U</i>-duality multiplets and nonperturbative superstring states
<i>U</i>-duality multiplets and nonperturbative superstring states
We employ an algebraic approach for unifying perturbative and nonperturbative superstring states on an equal footing, in the form of U-duality multiplets, at all excited string levels. In compactified type-IIA supertring theory we present evidence that the multiplet is labeled by two spaces, ``index'' space and ``base'' space, on which …