thinking about objects

A chi square distribution with ν degrees of freedom is a gamma distribution with shape ν/2 and scale 2. So in a mathematical sense, a chi square distribution “is a” gamma distribution. But should a class representing a chi square distribution inherit from a class representing a gamma distribution? The surprising answer is “no.” A rule called the “Lyskov Substitution Principle” (LSP) says this is a bad idea.

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