Ghost number 2As in the case of Maxwell theory, elements ofshould correspond to the gauge invariant operators in Type IIB theory.
Let us consider the case of flat space. The simplest thing we can reproduce is the Ramond-Ramond bispinor:
Here
is defined using the “left” part
of
—
see Eq. (38). It automatically satisfies the Dirac equation, because and
satisfy the Dirac equations (33).