Sparrow Language

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Intended audience

This document is intended for SEEK and Kepler developers. It is a DRAFT DESIGN DOCUMENT and does not reflect functionality as it currently exists in Kepler or SEEK. Comments and feedback are appreciated.

Introduction

Sparrow is a description-logic syntax that is meant as a "lightweight" alternative to RDF/S and OWL for defining ontologies. This document details the sparrow syntax. Note that in terms of expressivity, sparrow lies between RDF/S and OWL-DL.

Sparrow Basics

Sparrow, like description logics, represent ontologies using concepts, roles, and individuals.

In sparrow, concepts are defined using sentences. For instance, we can introduce a new concept called 'Vegetarian' using the following sentence.

concept Vegetarian

This sentence simply states that the 'Vegetarian' is a concept. Note that the term 'concept' is a reserved word in the sparrow language. A concept can be further elaborated using concept axioms, which are essentially more complex sentences (of a restricted form). Consider the following example.

concept Animal kind_of Organism

This sentence states that the concept 'Animal' is a sub-concept of the concept 'Organism'. In other words, every animal is an organism. The term 'kind_of' is a reserved word (sometimes referred to as "isa"). Both 'Animal' and 'Organism' are asserted as being concepts by this sentence. The sentence is equivalent to the following three sparrow sentences.

concept Organism
concept Animal
concept Animal kind_of Organism.

Multiple sentences defining the same concept can be combined through conjunction (and). For example, the sentences:

concept Animal kind_of Organism
concept Animal kind_of not Plant

can be combined into the sentence:

concept Animal kind_of Organism and not Plant

Here, the terms 'and' and 'not' are sparrow reserved words. The sentence states that an animal is an organism but not a plant.

Capitalization is not important in sparrow, thus the previous sentence is equivalent to:

CONCEPT animal KIND_OF organism AND NOT plant

Complex Concept Definitions

Packaging Sparrow Ontologies

A sparrow ontology is made up of a set of sparrow sentences. Typically an ontology would be stored in a single file, however, a file could conceivable store multiple ontologies. An ontology is started with the 'ontology' reserved word. An ontology can import definitions from other ontologies. The following example starts an ontology definition and imports an external ontology.

ontology myOnt 'http://seek.ecoinformatics.org/ontology1#'
import yourOnt 'http://seek.ecoinformatic.org/ontology2#'

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