−Table of Contents
Action lattices
Abbreviation: ActLat
Definition
An \emph{action lattice} is a structure A=⟨A,∨,∧,0,⋅,1,∗,∖,/⟩A=⟨A,∨,∧,0,⋅,1,∗,∖,/⟩ of type ⟨2,2,0,2,0,1,2,2⟩⟨2,2,0,2,0,1,2,2⟩ such that
⟨A,∨,0,⋅,1,∗⟩⟨A,∨,0,⋅,1,∗⟩ is a Kleene algebra
⟨A,∨,∧⟩⟨A,∨,∧⟩ is a lattice
∖∖ is the left residual of ⋅⋅: y≤x∖z⟺xy≤zy≤x∖z⟺xy≤z
// is the right residual of ⋅⋅: x≤z/y⟺xy≤zx≤z/y⟺xy≤z
Morphisms
Let AA and BB be action lattices. A morphism from AA to BB is a function h:A→Bh:A→B that is a homomorphism:
h(x∨y)=h(x)∨h(y)h(x∨y)=h(x)∨h(y), h(x∧y)=h(x)∧h(y)h(x∧y)=h(x)∧h(y), h(x⋅y)=h(x)⋅h(y)h(x⋅y)=h(x)⋅h(y), h(x∖y)=h(x)∖h(y)h(x∖y)=h(x)∖h(y), h(x/y)=h(x)/h(y)h(x/y)=h(x)/h(y), h(x∗)=h(x)∗h(x∗)=h(x)∗, h(0)=0h(0)=0, h(1)=1h(1)=1
Examples
Example 1:
Basic results
Properties
| Classtype | variety |
|---|---|
| Equational theory | |
| Quasiequational theory | undecidable |
| First-order theory | undecidable |
| Locally finite | no |
| Residual size | unbounded |
| Congruence distributive | yes |
| Congruence modular | yes |
| Congruence n-permutable | yes, n=2n=2 |
| Congruence regular | no |
| Congruence e-regular | yes |
| Congruence uniform | no |
| Congruence extension property | no |
| Definable principal congruences | no |
| Equationally def. pr. cong. | no |
| Amalgamation property | |
| Strong amalgamation property | |
| Epimorphisms are surjective |
Finite members
f(1)=1f(2)=1f(3)=3f(4)=20f(5)=149f(6)=1488