This is my notebook on quantum theory, which I use to organize my thoughts. I prefer algebraic approaches, as I find them more rigorous and elegant, and capable of providing a wealth of insights. 

My Group theory notebook. Group theory is the language that characterizes symmetry. In pursuit of mathematical rigor, I attempt to present my understanding of group theory in a structure resembling that of a textbook. 

This notebook is for Green's function, which is a powerful mathematical tool for characterizing correlations and interactions. From the viewpoint of holomorphic complex analysis, a number of useful physical insights naturally emerge.