• Let L1, L2 be two regular
languages
• L1, L2 are regular
languages
(the family of regular languages is closed
under complement)
• L1 È L2 is a
regular language
(the family of regular languages is closed
under union)
• L1 È L2 is a
regular language
(the family of regular languages is closed
under complement)
• L1 Ç L2 = L1 È L2 is a regular language (DeMorgan’s law)