1921
ID: 393
Emil Post introduces truth tables for propositional logic, providing decision procedure for propositional calculus
ID: 393
1921
ID: 1300
Baur-Fischer-Lenz 'Foundation of Human Heredity and Race Hygiene' published - heavily cited American eugenic research
ID: 1300
1921
ID: 1301
Dr. Lucien Howe's Draft Law requires $14,000 bonds (equivalent to $130,000+ today) from 'unfit' couples
ID: 1301
1921
ID: 1302
Radio broadcasting expands rapidly across America and Europe
ID: 1302
1921
ID: 1303
Walter Benjamin purchases Paul Klee's Angelus Novus monoprint
ID: 1303
1921
ID: 1304
Moscow church trials; 11 of 17 Orthodox officials ordered executed (1921-1922)
ID: 1304
1921
ID: 4229
Hollerith retires from C-T-R board, ends active involvement in punch card industry he created
ID: 4229
1921
ID: 4608
Emmy Noether proves ascending chain condition - foundation of commutative algebra
ID: 4608