strip_abss: always strip abstractions as far as possible, without keeping alternatives (which appear to be redundant anyway, but cause significant slowdown since discrimination nets collapse abstractions);
syntax: glob
*~
*.class
*.jar
.DS_Store
syntax: regexp
^heaps/
^browser_info/
^doc-src/.*\.aux
^doc-src/.*\.bbl
^doc-src/.*\.blg
^doc-src/.*\.dvi
^doc-src/.*\.idx
^doc-src/.*\.ind
^doc-src/.*\.log
^doc-src/.*\.out
^doc-src/.*\.rai
^doc-src/.*\.rao
^doc-src/.*\.toc