Explore the mathematical foundations and theoretical concepts behind lambda expressions in Java through this 46-minute Devoxx conference talk. Delve into Church Lambda calculus, the Entscheidungsproblem, and incompleteness theorem, presented from a scientific perspective using Java code examples. Discover the story behind lambda expressions, learn impressive math tricks, and witness unconventional implementations like a purely functional boolean based on lambda expressions. Gain insights into set theory, identity functions, lambda notation, boolean algebra, and natural numbers while understanding what "purely functional" truly means in programming.