Amazon rubber boom the expansion of Iquitos in Peru. The rubber boom occurred largely between 1879 and 1912. There was heightened rubber production and associated activities from 1942 to 1945 during the Second World War. Natural rubber is an elastomer, also known as tree gum, India rubber, and "caoutchouc," which comes from the rubber tree in tropical regions. Christopher Columbus was the one of the first Europeans to bring news of this odd substance back to Europe, but he was not the only one to report it. Around 1736, a French astronomer recalled how Amerindians used rubber to waterproof shoes and cloaks. He
History of type theory derivations in logics. Howard showed that the typed lambda calculus corresponded to intuitionistic natural deduction. (That is, natural deduction without the Law of excluded middle.) The connection between types and logic lead to a lot of subsequent research to find new type theories for existing logics and new logics for existing type theories. Nicolaas Govert de Bruijn created the type theory Automath as a mathematical foundation for the Automath system, which could verify the correctness of proofs. The system developed and added features over time as type theory developed. Per Martin-Löf found a type theory that corresponded to predicate logic