# 403: Convincing Pickup Line

Convincing Pickup Line |

Title text: Check it out; I've had sex with someone who's had sex with someone who's written a paper with Paul Erdős! |

## Explanation

A graph is a mathematical object consisting of **nodes** connected by lines called **edges**. The nodes could represent for example people, and the edges could represent a connection from having slept together. Now, Megan has such a graph. Arguably, a graph that is symmetric is nicer than a regular one, which is why Megan suggests that they should sleep together.

The title text is a small-world joke on the concept of Erdős number. Paul Erdős was a Hungarian mathematician renowned for his eccentricity and productivity. He holds the world record for the number of published math papers, as well as for the number of collaborative papers. A person's Erdős number is the "collaborative distance" between the person and Erdős. Paul Erdős's Erdős number is 0 by definition. All of his 511 collaborators have the Erdős number 1; anyone who has collaborated on a mathematical or scientific paper with any of those collaborators has an Erdős number of 2, and so on. Thus, if you have written a paper with someone who's written a paper with someone who's written a paper with Paul Erdős, your Erdős number is 3. If you know a mathematician or are a mathematician you can calculate his/her/your Erdős number here.

Comic 599: Apocalypse also references Erdős numbers.

## Transcript

- [Cueball and Megan sit at a small table in a cafe. Megan holds up a graph.]
- Megan: We're a terrible match. But if we sleep together, it'll make the local hookup network a symmetric graph.
- Cueball: I can't argue with that.

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