Derivation-homomorphisms

Lattice Homomorphisms Induced by Group Homomorphisms

Introduction. By a lattice homorphism of a group G onto a group G' we mean a single-valued mapping of the lattice L(G) of subgroups of G onto the lattice L(G') of subgroups of G', which preserves all unions and intersections, that is, which is subject to the conditions 1. (U,S,)0 = U,(S¿), 2. (r\vSr) = Ç)ASd>), for every (finite or infinite) set of subgroups 5„ of G. We call proper any l...

POMDP Homomorphisms

The problem of finding hidden state in a POMDP and the problem of finding abstractions for MDPs are closely related. In this paper, we analyze the connection between existing Predictive State Representation methods [3] and homomorphic reductions of Markov Processes [5, 6]. We formally define a POMDP homomorphism, then extend PSR reduction methods to find POMDP homomorphisms when the original PO...

n-Homomorphisms

Enumerating Homomorphisms

The homomorphism problem for relational structures is an abstract way of formulating constraint satisfaction problems (CSP) and various problems in database theory. The decision version of the homomorphism problem received a lot of attention in literature; in particular, the way the graph-theoretical structure of the variables and constraints influences the complexity of the problem is intensiv...

BCI-homomorphisms

In this paper X is a BCI-algebra and n is an element of N. Let D be a set, let f be a function from N into D, and let n be a natural number. Then f(n) is an element of D. Let G be a non empty BCI structure with 0. The functor BCI-powerG yielding a function from (the carrier of G) × N into the carrier of G is defined as follows: (Def. 1) For every element x of G holds (BCI-powerG)(x, 0) = 0G and...