2.6 Special names

Three kinds of conceptual graph are given distinguished names:

  1. A blank is an empty conceptual graph with no concepts, no relations, and no arcs. This is a blank:
    
         A blank
    
    The blank conceptual graph is the graph that says nothing about anything, and which therefore is true about everything.

  2. A singleton is a conceptual graph that consists of a single concept, but no conceptual relations or arcs. We have already seen an examle of a singleton:
         [God]
       A singleton
    

  3. A star is a conceptual graph that consists of a single relation and the concepts that are attached to its arcs. For example, these are both stars:
       [Bird]->(In)->[SycamoreTree]
       "A bird is in a sycamore tree"
    
       [Cat]->(On)->[Mat]
       "A cat is on a mat"
    


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