The EACSL was founded on July 14th 1992, by computer scientists and logicians from 14 countries. The Association acts as an international professional non-profit organization.

Computer science logic is an interdisciplinary field between mathematical logic and computer science. The EACSL promotes computer science logic in the areas of scientific research and education. It supports both basic and application oriented research. The association also intends to advance the connections between basic research and industrial applications.

Each year the Association organizes the Conference on Computer Science Logic (CSL) and grants the Ackermann Award, for outstanding dissertations in Logic in Computer Science.

# In evidence:

## Alonzo Church Award 2018

The 2018 Alonzo Church Award for Outstanding Contributions to Logic and Computation is given jointly to Tomas Feder and Moshe Y. Vardi for fundamental contributions to the computational complexity of constraint-satisfaction problems. Their contributions appeared in two papers:

1. Tomas Feder, Moshe Y. Vardi: Monotone Monadic SNP and Constraint Satisfaction. STOC 1993, 612-622.

2. Tomas Feder, Moshe Y. Vardi: The Computational Structure of Monotone Monadic SNP and Constraint Satisfaction: A Study through Datalog and Group Theory. SIAM J. Comput. 28(1), 57–104 (1998).

CONTRIBUTION SUMMARY: The Feder-Vardi project aimed at finding a large subclass of NP that exhibits a dichotomy (all problems are either in PTIME or NP-complete). The approach is to find this subclass via syntactic prescriptions. The paper identified a class of problems specified by “monotone monadic SNP without inequality”, which may exhibit this dichotomy. Feder and Vardi justified placing all three restrictions by showing, using Lad- ner’s theorem, that classes obtained by using only two of the above three restrictions do not show this dichotomy. They then explored the structure of this class. They show that all problems in this class reduce to the seemingly simpler class CSP – Constraint Satisfaction Problems. They divided CSP into subclasses and tried to unify the collection of all known polytime algorithms for CSP problems and extract properties that make CSP problems NP-hard. They conjectured that the class CSP (and therefore, also MMSNP) also satisfy the dichotomy property. This became known as the Feder-Vardi Dichotomy Conjecture. The Dichotomy Conjecture stimulated an exten- sive research program, which culminated in 2017 in two independent proofs, by A. Bulatov and by D. Zhuk, of its correctness.

Description of the contribution