> so it's probably a standard topic around the world (I think it's used to understand Fourier analysis in more advanced courses).
These notes are contained in a chapter or two of any standard linear algebra textbook. This can serve as a background when studying analysis. Analysis starts with considering the real line first, then moves on to the metric spaces, then the normed spaces etc. That's when this stuff comes in handy. Typically, in linear algebra course one is introduced to norms and their properties; but analysis doesn't care about this stuff - it's just that LA ideas are used to further generalize analysis concepts. Fourier analysis (in mathematically rigorous sense) is introduced relatively late in ones analysis edjumacation. But the subject is important to engineers and physicists, so they get to be introduced to Fourier stuff as early as possible, but with much of the analytic rigor stripped.