“…We will consider a category C as a (not necessarily simple) directed graph with vertex set Ob C and edge set Mor C . 1 We refer to the edges as arrows. The set of arrows between two vertices x, y ∈ Ob C is denoted by Mor C ( x, y ).…”
Section: Preliminariesmentioning
confidence: 99%
“…In this section we will define a structure that can be considered as a factorisation of pogroups. This work is inspired by binary relation orbifolds as discussed in [7,8,1]. However, these ideas are based on factor relations while we use a description here, that is more focused on the internal structure of the factor structure.…”
Section: Factorisationmentioning
confidence: 99%
“…However, when we consider a partial order as a directed graph, the direction of the arrows is preserved during the factorisation in many cases, while the factor graph of a simple graph is not necessarily simple. Even if the factor relation can be used to anchor unfolding information [1], this structure is usually not visible as a relation.…”
Section: Introductionmentioning
confidence: 99%
“…Conseqeuntly, the factored cyclic order relation contains the two triplets ( 0, 0 ), ( 0, 1 ), ( 3,1 ) and ( 0, 0 ), ( 3, 1 ), ( 0, 1 ) . This violates the antisymmetry condition of cyclic orders and cyclically ordered groups.…”
Orbits of automorphism groups of partially ordered sets are not necessarily congruence classes, i.e. images of an order homomorphism. Based on so-called orbit categories a framework of factorisations and unfoldings is developed that preserves the antisymmetry of the order Relation. Finally some suggestions are given, how the orbit categories can be represented by simple directed and annotated graphs and annotated binary relations. These relations are reflexive, and, in many cases, they can be chosen to be antisymmetric. From these constructions arise different suggestions for fundamental systems of partially ordered sets and reconstruction data which are illustrated by examples from mathematical music theory.
“…We will consider a category C as a (not necessarily simple) directed graph with vertex set Ob C and edge set Mor C . 1 We refer to the edges as arrows. The set of arrows between two vertices x, y ∈ Ob C is denoted by Mor C ( x, y ).…”
Section: Preliminariesmentioning
confidence: 99%
“…In this section we will define a structure that can be considered as a factorisation of pogroups. This work is inspired by binary relation orbifolds as discussed in [7,8,1]. However, these ideas are based on factor relations while we use a description here, that is more focused on the internal structure of the factor structure.…”
Section: Factorisationmentioning
confidence: 99%
“…However, when we consider a partial order as a directed graph, the direction of the arrows is preserved during the factorisation in many cases, while the factor graph of a simple graph is not necessarily simple. Even if the factor relation can be used to anchor unfolding information [1], this structure is usually not visible as a relation.…”
Section: Introductionmentioning
confidence: 99%
“…Conseqeuntly, the factored cyclic order relation contains the two triplets ( 0, 0 ), ( 0, 1 ), ( 3,1 ) and ( 0, 0 ), ( 3, 1 ), ( 0, 1 ) . This violates the antisymmetry condition of cyclic orders and cyclically ordered groups.…”
Orbits of automorphism groups of partially ordered sets are not necessarily congruence classes, i.e. images of an order homomorphism. Based on so-called orbit categories a framework of factorisations and unfoldings is developed that preserves the antisymmetry of the order Relation. Finally some suggestions are given, how the orbit categories can be represented by simple directed and annotated graphs and annotated binary relations. These relations are reflexive, and, in many cases, they can be chosen to be antisymmetric. From these constructions arise different suggestions for fundamental systems of partially ordered sets and reconstruction data which are illustrated by examples from mathematical music theory.
“…In order to develop decomposition techniques, which provide a link between the local and the global, it thus seems promising to take both viewpoints into account. As a concrete starting point we would like to study the connection between simplicial complexes and concept lattice orbifolds, a technique to "fold" concept lattices using symmetries of the context, which has been introduced by Daniel Borchmann and Bernhard Ganter [BG09].…”
International audienceFormal concept analysis associates a lattice of formal concepts to a binary relation. The structure of the relation can then be described in terms of lattice theory. On the other hand Q-analysis associates a simplicial complex to a binary relation and studies its properties using topological methods. This paper investigates which mathematical invariants studied in one approach can be captured in the other. Our main result is that all homotopy invariant properties of the simplicial complex can be recovered from the structure of the concept lattice. This not only clarifies the relationships between two frameworks widely used in symbolic data analysis but also offers an effective new method to establish homotopy equivalence in the context of Q-analysis. As a musical application, we will investigate Olivier Messiaen's modes of limited transposition. We will use our theoretical result to show that the simplicial complex associated to a maximal mode with m transpositions is homotopy equivalent to the (m − 2)–dimensional sphere
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