src/ZF/ZF_Base.thy
2017-08-18 wenzelm 2017-08-18 session-qualified theory imports: isabelle imports -U -i -d '~~/src/Benchmarks' -a;
2017-04-09 wenzelm 2017-04-09 clarified main ZF.thy / ZFC.thy, and avoid name clash with global HOL/Main.thy;