A logical knowledge base represents the world using a set of sentences with no explicit structure. An analogical representation, on the other hand, has physical structure that corresponds directly to the structure of the thing represented. Consider a road map of your country as an analogical representation of facts about the country—it represents facts with a map language. The two-dimensional structure of the map corresponds to the two-dimensional surface of the area.
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Give five examples of symbols in the map language.
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An explicit sentence is a sentence that the creator of the representation actually writes down. An implicit sentence is a sentence that results from explicit sentences because of properties of the analogical representation. Give three examples each of implicit and explicit sentences in the map language.
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Give three examples of facts about the physical structure of your country that cannot be represented in the map language.
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Give two examples of facts that are much easier to express in the map language than in first-order logic.
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Give two other examples of useful analogical representations. What are the advantages and disadvantages of each of these languages?