Paper: Missing figure in paper.md?

[hayesall]

Line 51 of the PDF (download) has a space followed by a period:

It looks like this is either a broken link, or a missing figure. The raw markdown of paper.md refers to a file: figures/Y_e.png

The `nnde` package was used to create a neural network with a single hidden layer and 10 hidden nodes and trained to solve this problem. The error in the trained solution for the case of $D=0.1$ is shown as a function of time in \autoref{fig:diff2d_error}.

![Difference between the trained neural network solution $\psi_t(x,y,t)$ and the analytical solution $\psi_a(x,y,t)$ of the diffusion problem in 2 spatial dimensions using `nnde` with 10 nodes.\label{fig:diff2d_error}](figures/Y_e.png)