C.L. Liu’s book is still under copyright. Unless the publisher (McGraw-Hill) or the author’s estate has explicitly released it into the public domain (which they have not), downloading a free PDF from a non-authorized source is copyright infringement.
Some of the key concepts and takeaways from "Elements of Discrete Mathematics" include:
: Detailed sections on permutations, combinations, and counting principles. Graph Theory : Covering representations, DFS/BFS, and spanning trees. Algebraic Structures : Introduction to groups, rings, and boolean algebra. Modern Computing Topics