13.3 Atoms: Their Types and Weights 247

13.3 Atoms: Their Types and Weights 247 alternatively as telling you what sort of data is associated with a Node. On the other hand, an example of a weight that may be attached to an Link or Node is a number representing a probability, or a number representing how important the Node or Link is. Obviously, hypergraphs may come along with various sorts of dynamics. Minimally, one may think about: e Dynamics that modify the properties of Nodes or Links in a hypergraph (such as the labels or weights attached to them.) e Dynamics that add new Nodes or Links to a hypergraph, or remove existing ones. 13.3 Atoms: Their Types and Weights This section reviews a variety of CogPrime Atom types and gives simple examples of each of them. The Atom types considered are drawn from those currently in use in the OpenCog system. This does not represent a complete list of Atom types referred to in the text of this book, nor a complete list of those used in OpenCog currently (though it does cover a substantial majority of those used in OpenCog currently, omitting only some with specialized importance or intended only for temporary use). The partial nature of the list given here reflects a more general point: The specific collection of Atom types in an OpenCog system is bound to change as the system is developed and experi- ment with. CogPrime specifies a certain collection of representational approaches and cognitive algorithms for acting on them; any of these approaches and algorithms may be implemented with a variety of sets of Atom types. The specific set of Atom types in the OpenCog system currently does not necessarily have a profound and lasting significance — the list might look a bit different five years from time of writing, based on various detailed changes. The treatment here is informal and intended to get across the general idea of what each Atom type does. A longer and more formal treatment of the Atom types is given in Part II, beginning in Chapter 20. 13.3.1 Some Basic Atom Types We begin with ConceptNode — and note that a ConceptNode does not necessarily refer to a whole concept, but may refer to part of a concept — it is essentially a "basic semantic node" whose meaning comes from its links to other Atoms. It would be more accurately, but less tersely, named "concept or concept fragment or element node." A simple example would be a ConceptNode grouping nodes that are somehow related, e.g. ConceptNode: C InheritanceLink (ObjectNode: BW) C InheritanceLink (ObjectNode: BP) C InheritanceLink (ObjectNode: BN) C ReferenceLink BW (PhraseNode "Ben’s watch") ReferenceLink BP (PhraseNode "Ben’s passport") ReferenceLink BN (PhraseNode "Ben’s necklace") HOUSE_OVERSIGHT_013163