Labels:crt screen | envelope | monitor | paper | reckoner | screen OCR: HEOREM ME CLASS F REGULAR LAN 6UAGES CLOSED CON CAT ENATION Recall: A,Az and and PROOF SAME APPZOACH Assume NFA recog nizes and NFA reco nizes Cants Construct NFA cognize A,-Az CASS C2507 UNDER APPEOACH recoy