Changes from Mercurial (hg https://foss.heptapod.net/isa-afp/afp-devel/ default)
Summary
- move parts of Min_Int_Poly from Hermite-Lindemann and Cubic_Quartic_Equations into Algebraic_Numbers
- ported Cubic_Quartic_Equations from AFP 2021 to devel
- merge of AFP 2021
- Cubic_Quartic_Equations sitegen
- new entry Cubic_Quartic_Equations
- sitegen for combinatorial design theory
- new entry: Combinatorial Design Theory
- sitegen for Three Circles
- new entry: Three Circles