Template:On This Day (nonfiction)/April 7

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  1761: Mathematician, philosopher, and minister Thomas Bayes dies. He is remembered for having formulated a specific case of the theorem that bears his name: Bayes' theorem.

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  1811: Astronomer, mathematician, and philosopher Hasan Tahsini born. He will become one of the most prominent scholars of the Ottoman Empire of the 19th century.

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  1866: Mathematician Erik Ivar Fredholm born. He will introduce and analyze a class of integral equations now called Fredholm equations. Fredholm's work on integral equations and operator theory will anticipate the theory of Hilbert spaces.

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  1889: Mathematician Paul David Gustav du Bois-Reymond dies. He worked on the theory of functions and in mathematical physics.

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  1899: Physicist and academic Petrus Leonardus Rijke dies. He explored the physics of electricity, and is known for the Rijke tube (which turns heat into sound, by creating a self-amplifying standing wave).

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  1903: United States Navy Admiral Edwin Thomas Layton born. Layton will serve as a Naval intelligence officer before and during World War II.

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  2014: Mathematician and academic Tim Cochran born. He will contribute to topology, especially low-dimensional topology, the theory of knots and links and associated algebra.

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  2009: Game designer Dave Arneson dies. He co-created the pioneering role-playing game Dungeons & Dragons with Gary Gygax.