Conservative Maltsev Constraint Satisfaction Problems

We show that for every finite structure B with a conservative Maltsev polymorphism, the constraint satisfaction problem for B can be solved by a symmetric linear Z2-Datalog program, and in particular is in the complexity class parity-L. The proof has two steps: we first present the result for a certain subclass whose polymorphism algebras are hereditarily subdirectly irreducible. We then show that every other structure in our class can be primitively positively constructed from one of the structures in the subclass. The second step requires different techniques and will be presented in a companion article.