偏序关系 bushy person wh business tion or trad be attended (a)Alphabetical (Lexicographical)Order:The reader is no doubt familiar with the usual alphabetical ordering of A*.That is: (i)<w,where A is the empty word and w is any nonempty word. (ii)Suppose u au'and v bu'are distinct nonempty words where a,b A and u',v'A*.Then u<v if a<b or if a=bbutu'<v' (b)Short-lex Order:Here A+is ordered first by length,and then alphabetically.That is,for any distinct words u,v in A*, u<v if lu<v or if lu=v but u precedes v alphabetically偏序关系