# cardinality predicates

## Monadic second-order logic with cardinality predicates ★★

Author(s): Courcelle

The problem concerns the extension of Monadic Second Order Logic (over a binary relation representing the edge relation) with the following atomic formulas:

- \item \item

where is a fixed recursive set of integers.

Let us fix and a closed formula in this language.

**Conjecture**Is it true that the validity of for a graph of tree-width at most can be tested in polynomial time in the size of ?

Keywords: bounded tree width; cardinality predicates; FMT03-Bedlewo; MSO