Template:Are You Sure/January 23

• ...that mathematician Werner Fenchel established the basic results of convex analysis and nonlinear optimization theory which would, in time, serve as the foundation for nonlinear programming?

• ...that physicist and glassblower Heinrich Geissler (Johann Heinrich Wilhelm Geißler) invented the Geissler tube, an early low pressure gas-discharge tube?

• ... that the illegal transdimensional drug Clandestiphrine was accidentally discovered by intelligence officer E. Howard Hunt during the course of an unauthorized experiment within MKUltra, the secret government mind-control project?

• ... that mathematician Leopold Kronecker was quoted by Heinrich Martin Weber (1893) as having said, "Die ganzen Zahlen hat der liebe Gott gemacht, alles andere ist Menschenwerk", commonly translated as "God made the integers, all else is the work of man"?