mathlib

3fe5c932 - feat(algebra/ring/boolean_ring): Turning a Boolean algebra into a Boolean ring (#6476)

feat(algebra/ring/boolean_ring): Turning a Boolean algebra into a Boolean ring (#6476) Define `as_boolring`, a type synonym to turn a Boolean algebra into a Boolean ring and show that `as_boolring` and `as_boolalg` are "inverse" to each other. Co-authored-by: Yaël Dillies <yael.dillies@gmail.com> Co-authored-by: Yaël Dillies <yael.dillies@gmail.com> Co-authored-by: YaelDillies <yael.dillies@gmail.com>