I want to ask a question about Total variation and bounded variation. In Principles of mathematical analysis, it seems to me that there is no section about this. What is the subject concerning this topic? Is it integration of Stieljes or what type of this topic should be contained in? I wonder why there is no mention of this topic in the book or I just can't find them.
P.S. I just have read this book for 4-5 units since I want to strengthen mathematical rigor.