Wikipedia has the following quote on John von Neumann:
Stan Ulam, who knew von Neumann well, described his mastery of mathematics this way: "Most mathematicians know one method. For example, Norbert Wiener had mastered Fourier transforms. Some mathematicians have mastered two methods and might really impress someone who knows only one of them. John von Neumann had mastered three methods." He went on to explain that the three methods were:
- A facility with the symbolic manipulation of linear operators;
- An intuitive feeling for the logical structure of any new mathematical theory;
- An intuitive feeling for the combinatorial superstructure of new theories.
And I am wondering what do 'logical structure' and 'combinatorial superstructure' mean in this context? Please explain these methods.
https://en.wikipedia.org/wiki/John_von_Neumann#Mastery_of_mathematics