The Expressive Power of Two−Variable Least Fixed−Point Logics
M. Grohe‚ S. Kreutzer and N. Schweikardt
Abstract
The present paper gives a classification of the expressive power of two-variable least fixed-point logics. The main results are:
- The two-variable fragment of monadic least fixed-point logic with parameters is as expressive as full monadic least fixed-point logic (on binary structures).
- The two-variable fragment of monadic least fixed-point logic without parameters is as expressive as the two-variable fragment of binary least fixed-point logic without parameters.
- The two-variable fragment of binary least fixed-point logic with parameters is strictly more expressive than the two-variable fragment of monadic least fixed-point logic with parameters (even on finite strings).
Book Title
Symposium on Mathematical Foundations of Computer Science (MFCS)
Pages
422 – 434
Publisher
Springer
Series
Lecture Notes in Computer Science
Year
2005