# Efficient Algorithms for Recognizing Weighted Tree-Adjoining Languages

arXiv: https://arxiv.org/abs/2310.15276 · HTML: https://mlsanity.com/paper/2310.15276/

## Key facts

- No citing papers in the map yet (data through 14 Oct 2026).
- Builds on 1 of its 22 references that are in the map.
- First posted on arXiv 23 Oct 2023.

## Builds on (most cited first, 1 of 1)

- [Convergence and Diversity in the Control Hierarchy](https://mlsanity.com/paper/2306.03628/) (2023)

## Abstract (arXiv)

The class of tree-adjoining languages can be characterized by various two-level formalisms, consisting of a context-free grammar (CFG) or pushdown automaton (PDA) controlling another CFG or PDA. These four formalisms are equivalent to tree-adjoining grammars (TAG), linear indexed grammars (LIG), pushdown-adjoining automata (PAA), and embedded pushdown automata (EPDA). We define semiring-weighted versions of the above two-level formalisms, and we design new algorithms for computing their stringsums (the weight of all derivations of a string) and allsums (the weight of all derivations). From these, we also immediately obtain stringsum and allsum algorithms for TAG, LIG, PAA, and EPDA. For LIG, our algorithm is more time-efficient by a factor of O(n|N|) (where n is the string length and |N| is the size of the nonterminal set) and more space-efficient by a factor of O(|Gamma|) (where |Gamma| is the size of the stack alphabet) than the algorithm of Vijay-Shanker and Weir (1989). For EPDA, our algorithm is both more space-efficient and time-efficient than the algorithm of Alonso et al. (2001) by factors of O(|Gamma|2) and O(|Gamma|3), respectively. Finally, we give the first PAA stringsum and allsum algorithms.