In the set of positive integers ordered by divisibility, greatest lower bounds are called “greatest common divisors” (g.c.d.'s). And least upper bounds are called “least common multiples” (l.c.m.'s). In this ordering, any finite set has an l.c.m., but infinite sets have no ...
including movies (by the American Film Institute) and books (by the Modern Library). Mathematicians were not immune, and at a mathematics conference in July, 1999, Paul and Jack Abad presented their list of "The Hundred Greatest Theorems." Their ranking is based on the...