Hi guys, I am reading some paper on Mellin Transform and its application in signal processing and I am totally stumped by phrases such as lebesgue space, square integrable, isometry, automorphism, measurable and essential supreme and such. Of course, when I look them up one by one I sort of get the concept (although still very confused about why people would go through all that mess to define these concepts as such), but I would like to be comprehensive about it. Where can I get a systematic understanding of these terms? Do I need a course in real analysis? If possible, can someone elaborate as to what a functional space mean?