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A set of configurations is unavoidable if every planar map contains at least one element of the set. A configuration L is called geographically good if whenever a member country M of L has any three neighbors N₁, N₂, N₃ which are not members of L then N₁, N₂, N₃ are consecutive (in some order) about M. The main result is a constructive proof that there exist finite unavoidable sets of geographically good configurations. This result is the first step in an investigation of an approach towards the Four Color Conjecture.
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Appel et al. (1976) studied this question.
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