  This paper presents \proverb\, a text planner for argumentative texts.
\proverb\'s main feature is that it combines global hierarchical planning and
unplanned organization of text with respect to local derivation relations in a
complementary way. The former splits the task of presenting a particular proof
into subtasks of presenting subproofs. The latter simulates how the next
intermediate conclusion to be presented is chosen under the guidance of the
local focus.
