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By V.A. Morozov, A.B. Aries, Z. Nashed. Any reasonable mathematical formulation of a physical problem requires that conditions (1)-(3) be satisfied. - Section 1. The Basic Problem for Linear Operators.
When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.