[Math] profitable way to read mathematical proofs

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Mathematical proofs are often presented in a sequential way, i.e., presenting definitions, building lemmas based on these definitions, building further results on these lemmas and finally invoking a combination of these results in a clever way to arrive at the desired result.

This is a neat approach to "present" mathematical proofs but one cannot find the motivation for the solution. By following proofs presented in this way, I profit very little because it is difficult to conceive why the author proves a certain result which apparently has no connection with the original problem (at that time). All I get is the understanding "why" this proof is correct.

So, is there a strategy to follow proofs in which the reader goes through the whole process the author underwent to arrive at the desired result?

Best Answer

Yes, there is a way to profitably read mathematical proofs, but it takes time. Here is an excerpt from the "note to the reader" in an excellent topology book:

"It is a basic principle in the study of mathematics, and one too seldom emphasized, that a proof is not really understood until the stage is reached at which one can grasp it as a whole and see it as a single idea. In achieving this end, much more is necessary than merely following the individual steps in the reasoning. This is only the beginning. A proof should be chewed, swallowed, and digested, and this process of assimilation should not be abandoned until it yields a full comprehension of the overall pattern of thought." - George Simmons - Introduction to Topology and Modern Analysis

And here is a (well-known) quote from the "Automathography" of Paul Halmos on how to read mathematics:

"Don't just read it; fight it! Ask your own questions, look for your own examples, discover your own proofs. Is the hypothesis necessary? Is the converse true? What happens in the classical special case? What about the degenerate cases? Where does the proof use the hypothesis?" -Paul Halmos

Other suggestions:

  • Read several sources.
  • Don't just read; ask someone to help explain it.
  • If you do understand it, try to reprove it or explain it to others.
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