I am currently taking a course in discrete mathematics. The literature used is "Discrete Mathematics And Its Applications by Kenneth H. Rosen" 6th ed., or 7th ed. I have encountered most of the topics from that book. I.e. Logic, naive set theory, &c. What I have encountered also is the definitions of functions in terms of images and mappings. But I always encounter this subject like some small sub-chapter in books. I.e. in the above mentioned book the following is illustrated To what area of mathematics does this sort of symbolism and illustration of functions belong? Is there a book which you recommend on this subject? Like i.e. in courses which I have had and in the discrete mathematics course, set theory is barely touched upon, so I ended up buying Axiomatic Set Theory by Patrick Suppes to have a broader treatment of the subject. But for the functions as images (Sorry that I do not have name for this subject) I do not know where to start searching for "deeper" treatment. I feel as if these books only teach me bits and pieces from functions as mappings and I want a serious treatment on these, if possible. I have also encountered mappings in S. Lang's Intro to linear algebra. Also do you recommend any books on discrete mathematics? The covered subjects in my course are: Logic and Proofs Sets and functions Algorithms, Integers and Matrices Induction and Recursion Counting Advanced Counting Techniques Logistic maps Celullar Automata Relations Graphs & Trees (Hamiltion and Euler circuit) According to the syllabus, from Logics until Counting it is only a repetition and a fast treatment of the subjects and starting with advanced counting techniques until graphs and trees is the main focus of this course.