What Work Is with the working class or work in general. This helps place this collection within the tradition of working class poetry. For instance, besides work, love also is a major theme for Levine in this collection. "What Work Is" is a poem primarily written for his brother, and the difficulty of expressing that love. Often enough the theme of love is expressed in a subdued way and is shadowing the bolder themes most largely associated with work. The poems feature different types of work, some of which reflect the actual work experience of the author. For instance, the poems "Fear and
Proof that π is irrational Proof that π is irrational In the 1760's, Johann Heinrich Lambert proved that the number (pi) is irrational: that is, it cannot be expressed as a fraction "a"/"b", where "a" is an integer and "b" is a non-zero integer. In the 19th century, Charles Hermite found a proof that requires no prerequisite knowledge beyond basic calculus. Three simplifications of Hermite's proof are due to Mary Cartwright, Ivan Niven, and Nicolas Bourbaki. Another proof, which is a simplification of Lambert's proof, is due to Miklós Laczkovich. In 1882, Ferdinand von Lindemann proved that is not just irrational, but transcendental as well.