sympy.abc のコードには，
Caveats ======= 1. As of the time of writing this, the names ``O``, ``S``, ``I``, ``N``, ``E``, and ``Q`` are colliding with names defined in SymPy. If you import them from both ``sympy.abc`` and ``sympy``, the second import will "win". This is an issue only for * imports, which should only be used for short-lived code such as interactive sessions and throwaway scripts that do not survive until the next SymPy upgrade, where ``sympy`` may contain a different set of names.
とある。また，sympy.abc にはギリシャ文字の大文字が定義されていない。したがって，今後は以下のようにしたらどうか，というメモ。 続きを読む