Sierpiński’s Theorem: GCH implies AC Continue reading
Monthly Archives: November 2025
Set Theory Jottings 18. The Axiom of Determinacy
Just denying the axiom of choice doesn’t buy you much. If you’re going to throw away AC, you should add some powerful incompatible axiom in its place. The Axiom of Determinacy (AD) has been studied in this light. Continue reading
Filed under Set Theory
From Kepler to Ptolemy 22
Libration Force
The Libration Force
Kepler coined the term “libration” for the oscillation of a planet’s distance from the Sun, approaching and receding. Continue reading
Diagonal Argument 