How to study relation and functions? I was interested in abstract algebra but the book I took up suggested I learn a bit of linear algebra, So I tried another book for it and then it went on and assumed I had knowledge of calculus, and continuing on this cycle I settled down that the base that would be starting this could possibly be Relation and Function(the one that is injective/bijective/surjective{is this true?}).
   What would be the best resource to study this and study this to an advanced level? I tried my go searching through the web and there are ample resources but all scattered, so I was in hoping to find a good book but I don't even know which branch of mathematics holds this particular topic. Please advice me a good resource for this.
 A: Here is a great (and free) resource you can use. Part four is all about relations, functions, and cardinality and there are plenty of practice problems to help cement your knowledge:
http://www.people.vcu.edu/~rhammack/BookOfProof/
It's a good book for laying a foundation and then moving on to more advanced topics in theoretical mathematics. It does not assume prior calculus knowledge but you may need to look a few things up as you go through it. Also, feel free to jump to relations and functions but I think starting at the beginning and working through will pay massive dividends for any theoretical math course you take down the line.
The great thing is, this book is more of an overview on methods of proof and notation that you will see in courses such as abstract algebra. The idea here is that you get broad exposure and an array of new perspectives on old ideas that you  have learned over the years... basically it helps you cross over from surface level mathematical thinking, to a deeper, richer understanding.
