I am an engineering student and I have been looking for this for such a long time. Real analysis, functional analysis. I hope in the future there will be complex analysis. This is extremely useful for digital signal processing stuff. One strange thing is that currently all the machine learning stuffs are not design for things that have complex number inside them####[['Real analysis', 'Mathematical_Related_Concept', 'POS'], ['functional analysis', 'Mathematical_Related_Concept', 'POS'], ['complex analysis', 'Mathematical_Related_Concept', 'POS'], ['machine learning stuffs', 'Mathematical_Related_Concept', 'NEU'], ['complex number', 'Mathematical_Related_Concept', 'NEU']]