Storage outside your home directory can be used to share files with others. Moreover, if you need a lot of storage space (more than 6 gigabytes), then your home directory is not big enough.
On linux machines one solution to this is to place some of the data under the directory /scratch in your local machine. Another solution is to use the directory /Data/math/math1 on your local machine, which points to a file-server. Both solutions have the problem that data in /scratch and in /Data/math/math1 is not backed up.
On windows machines the file-server mentioned above is found at \\ukl-felles\math1. Note that no backup is made of this directory.
Using /Data/math/math1 is the simplest way to share files with others in the math dept. It is possible to establish (unix style) groups to facilitate this further
If you chose one of the above solutions, then you should create a directory with your user name and place your files inside that directory. Be aware that you should set appropriate permissions to the files you place there.