Which symbol can be used to indicate a chemical reaction that takes place in the presence of a catalyst?

Common notation is to write the reaction conditions on top of the reaction arrow. For example, the Haber Process (3H2 + N2 - - > 2NH3), can use Iron as a catalyst, so Fe would be written above the reaction arrow to indicate reaction conditions. Any pressure or temperature, like the Haber process should be completed at 400-450 degrees celcius, should also be written above the arrow.