| Ast.Over (t1, t2) -> Ast.Over (k t1, k t2)
| Ast.Atop (t1, t2) -> Ast.Atop (k t1, k t2)
| Ast.Frac (t1, t2) -> Ast.Frac (k t1, k t2)
+ | Ast.InfRule (t1, t2, t3) -> Ast.InfRule (k t1, k t2, k t3)
| Ast.Sqrt t -> Ast.Sqrt (k t)
| Ast.Root (arg, index) -> Ast.Root (k arg, k index)
| Ast.Break -> Ast.Break