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Project-declaredLean 4.32.0

Has Deriv At of has Deriv At of Real comp

HasDerivAt.of_hasDerivAt_ofReal_comp

Plain-language statement

Let f:RRf:\mathbb R\to\mathbb R. If the same function, viewed as taking values in C\mathbb C, has derivative uCu\in\mathbb C at a real point zz, then uu is real and equals the ordinary real derivative of ff at zz.

analytic number theoryprime numbersasymptotics

Source project: Prime Number Theorem and More

Person-level attribution pending.

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