Kōsaku Yosida (吉田 耕作, Yosida Kōsaku, 7 February 1909, Hiroshima – 20 June 1990) was a Japanese mathematician who worked in the field of functional analysis. He is known for the Hille-Yosida theorem concerning C₀-semigroups. Yosida studied^[1] mathematics at the University of Tokyo, and held posts at Osaka and Nagoya Universities. In 1955, Yosida returned to the University of Tokyo.

You can help expand this article with text translated from the corresponding article in Japanese. (February 2024) Click [show] for important translation instructions. Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia. Consider adding a topic to this template: there are already 3,700 articles in the main category, and specifying|topic= will aid in categorization. Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article. You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing Japanese Wikipedia article at [[:ja:吉田耕作]]; see its history for attribution. You may also add the template {{Translated|ja|吉田耕作}} to the talk page. For more guidance, see Wikipedia:Translation.

This article relies largely or entirely on a single source. (April 2024)

• Einar Carl Hille
• Functional analysis