For this year’s annual Balliol Undergraduate Math Society (BUMS) dinner, Professor Robin Wilson, a former Balliol undergraduate himself, and now a professor at the Department of Mathematics from Open University, was supposed to address the audience — forty or so mathematicians, looking wholly uncomfortable in tuxedos and cocktail dresses.

Thing is, he never showed up.

The president of the society opened the evening’s talk.

“Professor Wilson had originally planned a talk centred around the 300 year old anniversary of Leonard Euler [pronounced as “Oiler”], but he was unable to attend.”

“So it’s fortunate that he was able to coax his good friend — Professor Euler himself — to come address us in his stead.”

And indeed, there he was.

Dining directly in front of me, swathed in elaborate gold robes and a funky hat with some furry creature on top — was Leonhard Euler himself.

“I realize that there’s some nasty rumours of my death floating around,” Euler said to us that night, “but they’re obviously false.”

“Now if my friend [Prof. R. Wilson] had been here, he’d undoubtedly spend all his time telling silly jokes — like the one about the geometry of kissing.”

“Oh,” he paused innocently, “do you all know the geometry of a kiss?”

We said nothing.

“Why, it’s an e-lip-twus of course!”

And in unison — perhaps fueled by the bad wine — we burst into an assortment of pained groans and wild cheering.

Euler was — and is still — known for his many great contributions to mathematics and physics. He is considered the most prolific author of all time (along with Paul Erdos), having published over 300 papers on a wide range of topics.

And today? What have you used recently that was discovered by Euler?

High school students will recognize his contributions to mathematical notation with the symbols of f(x) for functional notation, e (=2.7182..) for the base of the natural logarithm, i for the imaginary unit.

Scientists should also recognize his contributions to Calculus and Analysis which included, for example, his work on the analysis of infinite series’ and numerical methods of approximating functions.

But his most recreational problem was perhaps the one that involves the Seven Bridges of Königsberg:

The city of Königsberg, Prussia (now Kaliningrad, Russia) once included two large islands which were connected to each other and the mainland by seven bridges, thus separating the geography into four bodies of land.

The question many wondered was whether it was possible to travel in a route that passed each bridge once and only once (a route known today as an Eulerian Circuit).

Well Euler solved the stumper (in a fashion). And today, the Seven Bridges of Konigsberg problem is arguably considered the birth of the modern mathematical field known as Graph Theory, which is tied to a host of applications in, for example, computer science, network theory, and even sociology.

Later that night, I conversed openly with the esteemed mathematician.

“Professor, I was hoping that tonight, I’d bump into your friend Robin Wilson,” I said, feigning a sad look of ignorance.

“His book on Graph Theory saved me last year when I was taking a class on graphs.”

“Really?”, he said with a twinkle in his eye, “Well, I will definitely pass that on to my friend.”

And for the remainder of the dinner, the prolific and brilliant mathematician Leonhard Euler sat there — looking mighty pleased with himself.