This paper recounts the history of how calculus came to get a rigorous basis in terms of the algebra of inequalities. The result is a brief history of the 150 years from Newton/Leibniz to Cauchy that produced the foundations of analysis.
The origins of Cauchy's rigorous calculus by Grabiner, Judith V. Publication date 1981. Freely available at https://archive.org/details/originsofcauchys00judi
Tikhonov regularization method for a Cauchy problem for the Helmholtz equation in multiple dimensions-----，赵秋利，付初黎，This paper deals with a Cauchy problem for the Helmholtz equa-
tion in multiple dimensions.We want to obtain the solution u on the
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