In mathematics, a theorem is a statement that has been proven on the basis of previously established statements, such as other theorems, and previously accepted statements, such as axioms. The derivation of a theorem is often interpreted as a proof of the truth of the resulting expression, but different deductive systems can yield other interpretations, depending on the meanings of the derivation rules. The proof of a mathematical theorem is a logical argument demonstrating that the conclusions are a necessary consequence of the hypotheses, in the sense that if the hypotheses are true then the conclusions must also be true, without any further assumptions. The concept of a theorem is therefore fundamentally deductive, in contrast to the notion of a scientific theory, which is empirical.

Terrence Vance "Terry" Gilliam ( /ˈɡɪliəm/; born 22 November 1940) is an American-born British screenwriter, film director, animator, actor and member of the Monty Python comedy troupe. Gilliam is also known for directing several films, including Brazil (1985), The Adventures of Baron Munchausen (1988), The Fisher King (1991), 12 Monkeys (1995), and Fear and Loathing in Las Vegas (1998). The only "Python" not born in Britain, he took British citizenship in 1968.

Gilliam was born in Minneapolis, Minnesota, the son of Beatrice (née Vance) and James Hall Gilliam, who was a traveling salesman for Folgers before becoming a carpenter. Soon after, they moved to the nearby Medicine Lake.

The family moved to Panorama City, California, in 1952. Gilliam attended Birmingham High School where he was class president and senior prom King, was voted "Most Likely to Succeed", and achieved straight A's. During high school, he began to avidly read Mad magazine, which was then edited by Harvey Kurtzman; this later influenced his work.