## More Jokes

I’ve been collecting math jokes for many years. I thought I’ve seen them all. No. Inventive people continue to create them. I was recently sent a link to a math joke website that features many jokes that are new to me. Here are my favorites:

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With massive loss of generality, let $n=5$.

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How do you prove a cotheorem? Using rollaries.

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$0\to A\to B \to C \to 0$. Exactly.

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Let $\varepsilon\to 0$. There goes the neighborhood!

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Take a positive integer $N$. No, wait, $N$ is too big; take a positive integer $k$.

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Calculus has its limits.

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There is a fine line between a numerator and a denominator.

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There’s a marked difference between a ruler and a straightedge.

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Suppose there is no empty set. Then consider the set of all empty sets.

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Q: Why is it an insult to call someone “abelian”?

A: It means they only have a 1-dimensional character, and are self-centered.

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Q: What’s a polar bear?

A: A rectangular bear after a coordinate transform.

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A logician rides an elevator. The door opens and someone asks:

—”Are you going up or down?”

—”Yes.”