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
Type constructor be considered "built-in" in typed lambda calculi via currying. Abstractly, a type constructor is an "n"-ary type operator taking as argument zero or more types, and returning another type. Making use of currying, "n"-ary type operators can be (re)written as a sequence of applications of unary type operators. Therefore, we can view the type operators as a simply typed lambda calculus, which has only one basic type, usually denoted formula_1, and pronounced "type", which is the type of all types in the underlying language, which are now called "proper types" in order to distinguish them from the types of the