Serenus of Antinouplis

Serenus of Antinoöpolis (; c. 300 – c. 360 AD) was a Greek mathematician from the Late Antique Thebaid in Roman Egypt.

Life and work Serenus came either from Antinoeia or from Antinoöpolis, a city in Egypt founded by Hadrian on top of an older settlement. Two sources confirm that he was born in Antinoöpolis. It was once believed that he was born in Antissa, but this has been shown to have been based on an error.

Serenus wrote a commentary on the Conics of Apollonius, which is now lost. We hear from Theon of Alexandria that the main result of the commentary was that of a number of angles that are subtended at a point on a diameter of a circle that is not the center, then with equal arcs of that circle, the angle nearer to the center is always less than the angle farther away from the center. The work consists of thirty-three propositions. Proposition six proves the existence an oblique cylinder of the parallel circular sections subcontrary to the series of which the bases are two. Propositions twenty-nine to thirty-three deal with an optical problem. He gives a definition of parallels that was generally ridiculed.

In propositions one though fifty-seven of On the Section of a Cone, Serenus deals largely with the areas of triangular sections of right and scalene cones that are created by planes passing through the vertex. He shows when the area of a triangle of a certain class of triangles is at its maximum. Propositions fifty-eight through sixty-nine form a separate section of the book and deal with the volumes of right cones in relation to their heights, their bases and the areas of triangular sections through the axis.