Dioxazine Purple isn't quite the right hue to correctly neutralise yellow but it's usually the closest colour on our palettes. If anyone doesn't have a violet already just mix pretty much any dark blue with any deep red or crimson, it will work just as well if not better since you can nail the precise hue by tweaking the mix.
There is a problem with violet being so dark in value compared with yellows; the simple solution is to lighten the violet with white first until it's the same value as the yellow you're trying to shade. Although this sounds odd - adding white into a shadow colour - it replicates what you see in yellow quite accurately.
Regardless of whether you mix your violet or use a tube colour, add just a little of the violet/white mix into the yellow to get the first shadow mix, a little more for the middle shadow and for the deepest shadows add in some more of the original violet if it's not quite as dark as you'd like. If this darkest mix looks too colourful to you (depending on the yellow, mixing it with Dioxazine Purple can make something very similar to Burnt Sienna) just add in a touch of black or blue.
Einion