Properties

This page lists all the properties and their possible values that are currently part of some entry in this database.

Click on a property to get a brief explanation.

(Available soon) Click on the value of a property to see all classes that mention this property with the selected value.

Classtype variety, quasivariety, universal class, first-order class, second-order class, higher-order class
Equational theory decidable (PTIME, NPTIME, PSPACE, EXPTIME,…), undecidable, unspecified (so far)
Quasiequational theory decidable (PTIME, NPTIME, PSPACE, EXPTIME,…), undecidable, unspecified (so far)
First-order theory decidable (PTIME, NPTIME, PSPACE, EXPTIME,…), undecidable, unspecified (so far)
Locally finite yes, no, unspecified (so far)
Residual size $\kappa$ (cardinality), finite, unbounded
Congruence distributive yes, no, unspecified (so far)
Congruence modular yes, no, unspecified (so far)
Congruence n-permutable yes $n=?$, no, unspecified (so far)
Congruence regular yes, no, unspecified (so far)
Congruence e-regular yes, no, unspecified (so far)
Congruence uniform yes, no, unspecified (so far)
Congruence types permutational (1), abelian (2), Boolean (3), lattice (4), semilattice (5)
Congruence extension property yes, no, unspecified (so far)
Definable principal congruences yes, no, unspecified (so far)
Equationally def. pr. cong. yes, no, unspecified (so far)
Amalgamation property yes, no, unspecified (so far)
Strong amalgamation property yes, no, unspecified (so far)
Epimorphisms are surjective yes, no, unspecified (so far)