#computability and the Busy Beaver numbers; the Metamath folks are finding smaller and smaller Turing machines that only halt if ZF set theory is inconsistent. Stefan O’Rear has an entry with 1919 states, indicating that BB(1919) is uncomputable using ZF set theory, since it can’t prove its own consistency.
a #paper about something like #topology-optimization for #tensegrity structures (i.e. structures that incorporate preloads).
The "72-Year Rule": “the U.S. government will not release personally identifiable information about an individual to any other individual or agency until 72 years after it was collected for the decennial #census”, a rule codified in law since 1978, but established by Census Bureau Director Roy V. Peel in 1952. “After 72 years, the records are released to the public by the National Archives and Records Administration. In accordance with the 72-Year Rule, the National Archives released the 1930 records in April 2002 and most recently, the 1940 records were released April 2, 2012.”
Most of the 1890 US #census was lost in a fire in 1921.