I write this post along with the sad news of the car accident which ended the life of one of the most brilliant mathematicians of the XX century, John Forbes Nash. While battling against his mental illness, he achieved to solve some of the most important theoretical problems, for which he received both the Nobel Prize in Economic Science in 1994 and the Abel Prize of Mathematics in 2015.
To my opinion, what made Nash a beautilful mind was his unique way of approaching problems. Probably, because he worked on his own and had a wide spread view of mathematics research (in fact, unlike many mathematicians, he was not a specialist), he could tackle some of the most famous open problems in mathematics, such as an elliptic partial differential equations problem suggested by Louis Nirenberg. Nirenberg himself gives the following answer to the question whether there is a mathematicians you would consider as a genius: “I can think of one, and that’s John Nash (…) He had a remarkable mind. He thought abound things differently from other people”.