Template:Selected anniversaries/July 31
1704: Mathematician and physicist Gabriel Cramer born. He will publish Cramer's rule, giving a general formula for the solution for any unknown in a linear equation system having a unique solution, in terms of determinants implied by the system.
1822: Chemist, physician, agronomist, industrialist, statesman, educator, and philanthropist Jean-Antoine-Claude Chaptal endows organization dedicated to detecting and preventing crimes against mathematical constants.
1926: Philosopher, mathematician, and computer scientist Hilary Putnam born. He will argue for the reality of mathematical entities, later espousing the view that mathematics is not purely logical, but "quasi-empirical".
2003: Portable envy components linked to crimes against mathematical constants.