and is wrong into two ways: the search stack is generally not a
path, and does not run until the end of the STL container.
Remove it.
* src/tgbaalgos/tarjan_on_fly.cc, src/tgbaalgos/tarjan_on_fly.hh
(tarjan_on_fly): Do not inherit from the emptiness_search class,
because the check method will no longer return a counter example.
(tarjan_on_fly::check): Return only a boolean.
(tarjan_on_fly::build_counter): Delete.
* src/tgbatest/ltl2tgba.cc: Adjust.
src/tgbaalgos/tarjan_on_fly.hh,
src/tgbaalgos/tarjan_on_fly.cc,
src/tgbaalgos/nesteddfs.hh,
src/tgbaalgos/nesteddfs.cc,
src/tgbaalgos/minimalce.hh,
src/tgbaalgos/minimalce.cc: To correct a bug.
src/tgbaalgos/tarjan_on_fly.cc,
src/tgbaalgos/nesteddfs.hh,
src/tgbaalgos/nesteddfs.cc,
src/tgbaalgos/minimalce.hh,
src/tgbaalgos/minimalce.cc,
src/tgbaalgos/colordfs.hh,
src/tgbaalgos/colordfs.cc: four new algorithms for emptyness check.
src/tgbaalgos/gtec/ce.hh,
src/tgbaalgos/gtec/ce.cc: Adapt the counter exemple for the ce
object in minimalce.hh.
src/tgbatest/ltl2tgba.cc,
src/tgbatest/emptchk.test,
src/tgbaalgos/Makefile.am: Add files for emptyness-check.
* src/tgbaalgos/reductgba_sim_del.cc: Restrict to degeneralize automata.
* src/tgba/tgbareduc.hh: src/tgba/tgbareduc.cc: Merge transition
for scc reduce.
