LBT NEWS -- history of user-visible changes.  29th December 2004
Copyright © 2001,2002,2004 Marko Mäkelä
Copyright © 2004 Heikki Tauriainen
See the end for copying conditions.

* LBT 1.2.2 and LBT 1.1.1 fix problems with run-time stack overflow
(no user-visible changes)

** The use of recursion in previous versions of LBT may lead to a crash
with large input formulae due to run-time stack overflow.  LBT 1.1.1 and
LBT 1.2.2 attempt to improve the robustness of the tool by replacing recursion
with explicit stacks.  The difference between LBT 1.1.1 and LBT 1.2.2
is the same as the difference between LBT 1.2 and LBT 1.1, i.e., LBT 1.2.2
may be more efficient on small input formulae.

* LBT 1.2.1 improves the documentation only

** A few minor errors were corrected in the grammar description.

** The pictures of the automata were redrawn with anti-aliased fonts.

* LBT 1.2 is an optimized release with no user-visible changes

** Formula sets are now maintained in bit vectors
instead of Standard Template Library sets.  This typically reduces
the memory usage and improves the speed of the program.  The generated
automata should be of the same size as with LBT 1.1, but the acceptance
sets for the states can be displayed in a slightly different order.

* New operators in LBT 1.1

** The equivalence and nonequivalence (exclusive or) operators are supported
natively by the translation algorithm of LBT 1.1.  When these operators are
implemented in the core language, formulae that contain these operators can
be expressed in a much more compact way.

* LBT 1.0

** A complete rewrite of the algorithms from Mauno Rönkkö's LBT2BUCHI
and Heikki Tauriainen's super_aasa_lbt.

** Common subformula elimination reduces the size of the generated automata.


----------------------------------------------------------------------
Copyright information:

Copyright © 2001,2002,2004 Marko Mäkelä
Copyright © 2004 Heikki Tauriainen

   Permission is granted to anyone to make or distribute verbatim copies
   of this document as received, in any medium, provided that the
   copyright notice and this permission notice are preserved,
   thus giving the recipient permission to redistribute in turn.

   Permission is granted to distribute modified versions
   of this document, or of portions of it,
   under the above conditions, provided also that they
   carry prominent notices stating who last changed them.

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