Well-Nested Context Unification [chapter]

Jordi Levy, Joachim Niehren, Mateu Villaret
2005 Lecture Notes in Computer Science  
Context unification (CU) is the open problem of solving context equations for trees. We distinguish a new decidable variant of CU well-nested CU -and present a new unification algorithm that solves well-nested context equations in non-deterministic polynomial time. We show that minimal well-nested solutions of context equations can be composed from the material present in the equation (see Theorem 1). This property is wishful when modeling natural language ellipsis in CU.
doi:10.1007/11532231_11 fatcat:kh23avzugrgrfmnm544ij4tkum