Induction is rescuing us…
	• Induction step – assume for i, prove for i+1. – consider two numbers: X, Y.  Say Xi is ith digit of X (from the right) • Xi+1 < Yi+1 then i+1th BinSort will put them in order • Xi+1 > Yi+1 , same thing • Xi+1 = Yi+1 , order depends on last i digits.  Induction hypothesis says already sorted for these digits. (Careful about ensuring that your BinSort preserves order aka “stable”…)