Communicating a Proof


Saunders Mac Lane (1909 – 2005) was an American mathematician who became known for being one of the proponents of category theory. During an interview with The Mathematical Review in 1976, he reminisced about the time when he was learning about geometry in high school:

I recall one occasion involving a theorem about a triangle: I knew that the specific shape of the triangle did not matter and that its vertices could be lettered at will. So when I went to the board, I drew the triangle upside down, changed the letters labeling the vertices, and presented the proof at flank speed, all to the evident distress of my teacher, as some of the students (my friends) egged me on. In retrospect, it is apparent that I understood the proof from my first geometry class, but that I did not at all see how to communicate the proof to my fellow students; I must have been a real nuisance to the young teacher.

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My name Edmark M. Law. I work as a freelance writer, mainly writing about science and mathematics. I am an ardent hobbyist. I like to read, solve puzzles, play chess, make origami and play basketball. In addition, I dabble in magic, particularly card magic and other sleight-of-hand type magic. I live in Hong Kong. You can find me on Twitter` and Facebook. My email is

3 thoughts on “Communicating a Proof

  1. I would like to see you in reality counting difficult mathematical problems. Would have been fun!😊 I have a buddy I went with electricity and automation with. He had become unemployed after a pharmaceutical company was sold to … USA! He had a hard time getting a job because he was overqualified!😁
    He wrote third-degree equations on the chalkboard to explain things, but I wasn’t on the same IQ level as him!I😂😂 called him several times when I would switch engines on different objects (I do not like electricity, PLC is my thing.) And he knew everything I wanted to know, without to see it.


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