Complexity Results on Balanced Context-Free Languages

Abstract. Some decision problems related to balanced context-free languages are important for their application to the static analysis of programs generating XML strings. One such problem is the balancedness problem which decides whether or not the language of a given contextfree grammar (CFG) over a paired alphabet is balanced. Another important problem is the validation problem which decides whether or not the language of a CFG is contained by that of a regular hedge grammar (RHG). This paper gives two new results; (1) the balancedness problem is in PTIME; and (2) the CFG-RHG containment problem is 2EXPTIMEcomplete.

• Type: Conference
• Year: 2007
• Where: FOSSACS
• Authors: Akihiko Tozawa, Yasuhiko Minamide
• Keywords: Applied Computing, Balanced Context-free Languages, Balancedness Problem, CFG-RHG Containment Problem, FOSSACS 2007