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The pointwise product of two functions is another function, obtained by multiplying the image of the two functions at each value in the domain. If ''f'' and ''g'' are both functions with domain ''X'' and codomain ''Y'', and elements of ''Y'' can be multiplied (for instance, ''Y'' could be some set of numbers), then the pointwise product of ''f'' and ''g'' is another function from ''X'' to ''Y'' which maps ''x'' ∈ ''X'' to ''f''(''x'')''g''(''x''). ==Formal definition== Let ''X'' and ''Y'' be sets, and let multiplication be defined in ''Y''—that is, for each ''y'' and ''z'' in ''Y'' let the product : given by be well-defined. Let ''f'' and ''g'' be functions . Then the pointwise product is defined by : for each ''x'' in ''X''. In the same manner in which the binary operator ⋅ is omitted from products, we say that . 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「pointwise product」の詳細全文を読む スポンサード リンク
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