Cfxtrjtrk

I have no way of knowing if it was accidental or intentional, but the expression

$$C(u,n,t_1,dots,t_k)$$

occurs on p. 95 of Paul J. Cohen, Set Theory and the Continuum Hypothesis, W. A. Benjamin, Inc., New York, 1966, in section III.4, "Proof of AC and GCH in L".

This wasn't published, but I'll post it anyway. I apologize for not using MathJax below, but the plain text representation more accurately represents the handwriting, which is relevant to the story.

In my freshman linear algebra class, the professor illustrated the calculation of the determinant a generic $3 times 3$ matrix
$$left( begin{array}{ccc} a & b & c \ d & e & f \ g & h & i end{array} right)$$
via the Laplace expansion by minors down the first column. One term (not including the leading minus sign) is

"d (bi-ch)".

Some wise guy asked "Does this also work for calculating the permanent?", correctly predicting what was about to happen. The professor cheerfully responded "Yep, you just change all the minuses to plusses!" and changed it to

"d (bi+ch)".

When everyone laughed, he looked horrified and erased it right away.

The set of associated primes of an $R$-module $M$ is denoted by
$$mathrm{Ass}_R(M) $$
This is universal notation. Look in any textbook on commutative algebra.

My Linear Algebra lecturer kept on talking about $s in X$ and $v_j$. The latter is more of a stretch, but I imagine both occur very frequently in the literature.

Perhaps a bit obscure, but perfectly serious:

The Cox-Zucker machine is an algorithm that determines if a set of sections provides a basis for the Mordell–Weil group of an elliptic surface $E → S$ where $S$ is isomorphic to the projective line.

Crossing to a different science (so slightly off topic!). But Proton Enhanced Nuclear Induction Spectroscopy is a genuine NMR spectroscopy technique (and it's in a field where everything is known by acronyms so yeah it was deliberate...) https://en.wikipedia.org/wiki/Proton-enhanced_nuclear_induction_spectroscopy

Sadly it's usually known as Cross Polarisation (CP) nowadays.

My Linear Algebra professor once referenced a matrix with $A_{RS}$. When the students laughed, he told us about a pamphlet from the end of the Thirty Years' War titled "Mars is in the Ars".

I remember well that we had a book from a Professor Fick during my physics studies, and used to refer to it as the 'Fick-Book', often in public; to the consternation and shock of other people around us (in the tram, or in cafes)

[Fick is the german work for 'fuck']
https://de.m.wikipedia.org/wiki/Eugen_Fick

One well-known example, that arose when branes were introduced into String Theory (physics), was that people studying $p$-dimensional branes were branded “$p$-brane theorists”. (Like some examples above, that is perhaps more a homonym of an explicative.)

It's more engineering than mathematics, but there is a well-known supplier of electronic test equipment called Wayne Kerr. You have to believe that the company name was chosen innocently by someone naive who hadn't talked to their shop-floor workers.

The 1996 University of Cambridge Mathematical Tripos IB (second year undergraduate exam), Paper 1, had question 5D on Linear Mathematics ending with the sentence:

Define the dual map $alpha^*$ and prove that $alpha^* f_r^* = sum_{s=1}^n a_{rs}e_s^*$, $1 le r le m$.

There is a certain Dr. Bagger who is active in Theoretical Physics (quite mathematical, at least to us experimentalists). He often works in collaboration with others and since his name is quite near the beginning of the alphabet, his citations lead to a witty coincidence (probably funnier for British people...).

From page 181 of https://arxiv.org/pdf/hep-ph/0203079.pdf

I'm currently reading this paper https://arxiv.org/abs/1207.4750 (which, admittedly is physics not math) on page 5 they are describing a general procedure so they just give an example of an action which they denote as

$$S_{ex}$$

S because that is the traditional way of denoting an action, and ex because it's just a generic example that they trying to use

This happend digital electronic class. Teacher was explaining some circuit that she drawn on blackboard. Output was Q0 to Q7, every time she say Q2 we were chuckling. It took her some time to realize that Q2 (pronounced kudwa) is very similar to word kurwa (fuck or bitch, depend on context).