Edward Brian Davies was a professor of Mathematics, King's College London (1981–2010), and was the author of the popular science book Science in the Looking Glass: What do Scientists Really Know. In 2010, he was awarded a Gauss Lecture by the German Mathematical Society.
Example 1.2.5 The Laplacian -Delta is the most important operator and is also one of the oldest. It was studied by Laplace in conecction with the theory of gravitation. The Laplacian operator is symmetric on the space of smooth functions with compact support (or vanishing at the infinity?)