Brown-Robinson Theorem

The Brown-Robinson Theorem states that two distinct, non-empty, finite sets can be placed in a one-to-one correspondence if and only if they contain the same number of elements. In simpler terms, it means if you have two different groups of items, you can pair them up perfectly without any leftovers if the groups are equal in size. This theorem is fundamental in understanding sizes of sets in mathematics, particularly in areas like combinatorics and set theory, and it highlights the importance of counting and comparing quantities effectively.