In this paper, the concept of type 2 expressions (2Es for short) is briefly introduced, and it is proved strictly that CFL class is precisely the language class expressed by 2Es. A new proof using 2Es to pumping lemma...In this paper, the concept of type 2 expressions (2Es for short) is briefly introduced, and it is proved strictly that CFL class is precisely the language class expressed by 2Es. A new proof using 2Es to pumping lemma for CFLs is geven.展开更多
文摘In this paper, the concept of type 2 expressions (2Es for short) is briefly introduced, and it is proved strictly that CFL class is precisely the language class expressed by 2Es. A new proof using 2Es to pumping lemma for CFLs is geven.
