Search the Dagstuhl Website
Looking for information on the websites of the individual seminars? - Then please:
Not found what you are looking for? - Some of our services have separate websites, each with its own search option. Please check the following list:
Schloss Dagstuhl - LZI - Logo
Schloss Dagstuhl Services
Within this website:
External resources:
  • DOOR (for registering your stay at Dagstuhl)
  • DOSA (for proposing future Dagstuhl Seminars or Dagstuhl Perspectives Workshops)
Within this website:
External resources:
Within this website:
External resources:
  • the dblp Computer Science Bibliography

Research Meeting 23516

Formalising the Notion of Algorithm

( Dec 17 – Dec 21, 2023 )

(Click in the middle of the image to enlarge)

Please use the following short url to reference this page:




The notion of algorithm, which predates even the earliest developments of computer science, is nowadays omnipresent in our digitalised society. However, no consensus exists as to what an algorithm is. Even if computer scientists have an intuitive idea of what an algorithm is in the context of informatics, no formal definition exists.

This meeting will gather researchers in computer science, mathematical logic, and philosophy of science around this question of formalising the notion of algorithm. Indeed, the question is fundamentally interdisciplinary as such a formalisation should be accompanied with a conceptual delimitation of the concept. The lack of formal definition of the notion of algorithm has been observed for many years, notably by Richard Shore who identified it in 2001 as one of three remaining "not original and probably pie-in-the-sky" problems. In particular, it lead to proposals for such formalisation: Y. Gurevich introduced the notion of abstract state machines, and Y. Moschovakis introduced the notion of recursors. More recently, T. Seiller proposed a new formalisation, based on work in program semantics and computational complexity. The objective of the meeting will be to compare these approaches from a mathematical and a conceptual point of view, as well as through a confrontation with computer science practice.

Copyright Alberto Naibo and Thomas Seiller

  • Logic in Computer Science
  • Discrete Mathematics