In the context the order of iterators is that the returned value is
always positive

... because most developers were copy-pasting the preambule anyway and
did not pay any attention to change it.

Also, I think that git does better job in managing that.

The case (b*+a)* was only optimized to (b+a)* by lemma V4.

Tomáš Pecka authored 4 years ago and Jan Trávníček committed 4 years ago

Although #pragma once is not a standard, compilers nowadays usually
support it. We don't have any tricky build system so we should be OK.

This also fixes many errors regarding using reserved identifiers (names
starting with double underscore).