# Found a math equation graffitied on a wall. What's it trying to say?

1. Nov 24, 2012

### Tonber

Hello everyone, longtime reader, first time poster.

A friend and I discovered this piece of math graffitied on an obscure laneway wall in Melbourne. I find it a bit mindblowing that someone would go to all this effort, particularly in a place where very few people are going to see it. As you can see from the video, it is quite neat and meticulously done.

I understand parts of it, there are some parts I don't understand, but really I have two major questions I was hoping you guys could help me out with.

1. What is it trying to say overall. What is all this math 'for'?

2. (Bonus marks) What drove this person to do this?

Last edited by a moderator: Sep 25, 2014
2. Nov 24, 2012

### Staff: Mentor

Looks a bit like thermodynamics, but I don't recognize the equations.

$\frac{d[\ln(n)]}{dn}=\frac{1}{n}$

$d[\ln(P)]=-\sum_j [\ln(n_j)+1] dn_j$ => $\sum_j dn_j = 0$ and $\sum_j u_j dn = 0$
=> $d[\ln(P)]=\sum [-\ln(n_j)+a-1+bu_j]dn_j=0$
=> $-\ln(n_j)+a-1+bu_j=0$ or $n_j=\epsilon^{a-1+bu_j}=\epsilon^{a-1}\epsilon^{bu_j}=A\epsilon^{bu_j}$
[Based on the structure, those formulas would be equivalent without the minus sign and if $\epsilon=e$.]
=> $\ln(n_j)+a-1+bu_j$ (that is not an equation)

1:45-2:42 is some messy sketch.