This was done by Alonzo Church in 1936 with the concept of "effective calculability" based on his λ-calculus and by Alan Turing in the same year with his concept of Turing machines.
Detta gjorde Alonzo Church år 1936 med begreppet "effektiv kalkylerbarhet" baserat på sin lambdakalkyl och Alan Turing samma år med begreppet Turingmaskin.