He is best known for his work in the field that eventually became known as computability theory .
Emil Leon Post ( February 11 , 1897 -- April 21 , 1954 ) was an American mathematician and logician .
Emil Leon Post is best known for Emil Leon Post 's work in the field that eventually became known as computability theory .
Emil Leon Post ( February 11 , 1897 -- April 21 , 1954 ) was an American mathematician and logician .