1
vote
1answer
69 views

Satisfiability problem for FOL[<,R]

Let FOL[<,R] be the fragment of first-order logic enriched with two relational symbols < and R and the first-order axioms that say: < is a strict partial order and R is an irreflexive and ...
3
votes
1answer
208 views

Can a polynomial size CFG over large alphabet describe any of these languages:

Can a polynomial size CFG over large alphabet describe any of these languages: Each terminal appears 0 or 2 times Word repetition {www* | w \in \Sigma *} (word repetition of an arbitrary word w) ...
2
votes
1answer
247 views

Restricted read twice BDDs and context free grammars

Several papers give poly-time algorithms for constrained paths on labelled graphs, e.g. [1] Quote: Given an alphabet Σ, a (directed) graph G whose edges are weighted and Σ-labeled, and a formal ...
5
votes
5answers
686 views

Can a polynomial size CFG over large alphabet describe a language, where each terminal appears even number of times?

Can a CFG over large alphabet describe a language, where each terminal appears even number of times? If yes, would the Chomsky Normal Form be polynomial in |Σ| ? EDIT: What about a language where ...