caption: Church <PERSON>, 1936, An unsolvable problem of elementary number theory.
exif: {"Image DocumentName": "Church Alonzo Church, 1936, An unsolvable problem of elementary number theory.", "Image ImageDescription": "Introduced recursive functions and l-definable functions and proved these classes equivalent. We \u2026 define the notion \u2026 of an effectively calculable function of positive integers by identifying it with the notion of a recursive function of positive integers.", "Image XResolution": "200", "Image YResolution": "200", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}