  Linear logic programming uses provability as the basis for computation. In
the operational semantics based on provability, executing the
additive-conjunctive goal $G_1 \& G_2$ from a program $P$ simply terminates
with a success if both $G_1$ and $G_2$ are solvable from $P$. This is an
unsatisfactory situation, as a central action of \& -- the action of choosing
either $G_1$ or $G_2$ by the user -- is missing in this semantics.
  We propose to modify the operational semantics above to allow for more active
participation from the user. We illustrate our idea via muProlog, an extension
of Prolog with additive goals.
