2006-07-25 wenzelm 2006-07-25 tuned;
2006-07-25 haftmann 2006-07-25 renamed Name.give_names to Name.names and moved Name.alphanum to Symbol.alphanum
2006-07-21 haftmann 2006-07-21 added give_names and alphanum
2006-07-19 wenzelm 2006-07-19 export make_context, is_declared;
2006-07-13 wenzelm 2006-07-13 do not export make_context; initial context: declare empty names; variants: no special treatment of empty names;
2006-07-12 wenzelm 2006-07-12 variants: special treatment of empty name;
2006-07-11 wenzelm 2006-07-11 clean: no special treatment of empty name; declare, invent: clean arguments;
2006-07-11 wenzelm 2006-07-11 Names of basic logical entities (variables etc.).