Diagonal substitution doubles the congruence degree: `f ≡ g` through `M` gives `qdiag f ≡ qdiag g` through `2M + 1`.

Initializing...

Diagonal substitution doubles the congruence degree: `f ≡ g` through `M` gives `qdiag f ≡ qdiag g` through `2M + 1`. · Prove2Me