These articles proceed beyond the minimum knowledge of linear algebra needed in quantum mechanics. The Kronecker delta symbol and the Levi-Civita symbol are frequently used in general relativity. The concept of the determinant is important in understanding Jacobian, which we will cover in the section “A Crash Course in Calculus, the fourth part.” The article on the rotation and the Lorentz transformation is important in understanding 4-vector, which we will cover in the section “Theory of Special Relativity and 4-vector.” The last three articles deal with the concept of the group which plays a very important role in math and physics. Math students learn about group in details in courses titled “abstract algebra” for two semesters in their sophomore year.