I am just begining to explore different graduate school options. It seems that there are a lot of financial math fields that are very similar. I am sure this question would require a very long answer, but what are the basic differences between, financial engineering , quantitative finance, industrial engineering, operations research? Are the basically all the same? Do certain ones restrict what type of work you can do? Is any considered the most difficult? Do they all involve the same level of mathematics? Thanks very much.