A hierarchy of deterministic context-free omega-languages
Twenty years ago, Klaus. W. Wagner came up with a hierarchy of omega-regular sets that actually bears his name. It turned out to be exactly the Wadge hierarchy of the sets of 0)omega-words recognized by deterministic finite automata. We describe the Wadge hierarchy of context-free omega-languages, which stands as an extension of Wagner's work from automata to pushdown automata. (C) 2002 Elsevier Science B.V. All rights reserved.
deterministic context-free omega-languages wadge hierarchy pushdown automata