[CategoryRefactoring/RefactoringLanguage]

See Bill Murphy and Martin Fowler's page at http://www.refactoring.com/catalog/reverseConditional.html

This refactoring pattern appears to be a subset of RefactorNegateIf.


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Related:
* ConditionalProbability
* http://www.richland.edu/james/lecture/m170/ch05-cnd.html