Lars Kristiansen

Below you find a list over my current research interests together with some selected papers.

Weak First-Order Theories (selected papers):

• Kristiansen, L. & Murwanashyaka, J.: First-Order Concatenation Theory with Bounded Quantifiers. Archive for Mathematical Logic  (2020). doi: 10.1007/s00153-020-00735-6
• Kristiansen, L. & Murwanashyaka, J.: On Interpretability Between some Weak Essentially Undecidable Theories.   LNCS   (2020). doi: 10.1007/978-3-030-51466-2_6

You can read more about  first-order theories in Wikipedia.  

Computable Analysis (selected papers):

• Georgiev, I.,  Kristiansen, L. & Stephan, F.: Computable Irrational Numbers with Representations of Surprising Complexity. Annals of Pure and Applied Logic (2020).  doi: 10.1016/j.apal.2020.102893     Preprint.
• Kristiansen, L.: On Subrecursive Representability of Irrational Numbers, Part II. Computability   (2018) . doi: 10.3233/COM-170081
• Kristiansen, L.: On Subrecursive Representability of Irrational Numbers. Computability (2017). doi: 10.3233/COM-160063

You can read more about computable analysis in Wikipedia.

Subrecursive Degree Theory (selected papers):

• Kristiansen, L., Schlage-Puchta, J. & Weiermann, A: Streamlined Subrecursive Degree Theory.  Annals of Pure and Applied Logic (2012). doi: 10.1016/j.apal.2011.11.004
• Kristiansen, L.:  A Jump Operator on Honest Subrecursive Degrees. Archive for Mathematical Logic  (1998). doi: 10.1007/s001530050086

You cannot read more about subrecursive degree theory in Wikipedia. But you can read about  the  Grzegorczyk hierarchy.  Subrecursive degrees are in some sense a generalization of the Grzegorczyk hierarchy.

Implicit Computational Complexity and related stuff (selected papers):

• Kristiansen, L.: Reversible Computing and Implicit Computational Complexity. link: click here   Science of Computer Programming (2021)
• Kristiansen, L., Ben-Amram, A.  & Jones, N. D.:  Linear, Polynomial or Exponential? Complexity Inference in Polynomial Time.  LNCS   (2008).  See  here
• Kristiansen, L.: Neat function Algebraic Characterizations of LOGSPACE and LINSPACE. Computational Complexity (2005). doi:  10.1007/s00037-005-0191-0
• Kristiansen, L. & Niggl, K.-H.: On the Computational Complexity of Imperative Programming Languages. Theoretical Computer Science  (2004). doi: 10.1016/j.tcs.2003.10.016

You can read more about implicit computational complexity in Wikipedia.