  In this note, we give a formulation of log structures for derived stacks
using Olsson's log stack. The derived cotangent complex is then Olsson's
logarithmic cotangent complex, which (unlike Gabber's) is just given by log
differential forms in the log smooth case. The derived moduli stack of log
stable maps then produces the desired virtual tangent space and obstruction
theory on the underlying underived stack.
