A sequence of separate runs will select the tiddlers that match any of the runs. We can use this to find recipes that serve either 3, 4 or 5 people:
[serving[3]] [serving[4]] [serving[5]]
If we want to ignore vegetarian recipes that serve 4, we can say this:
[serving[3]] [serving[4]!tag[Vegetarian]] [serving[5]]
By default, each run considers every tiddler in the wiki. But we can use a + sign to force a run to consider only the tiddlers that were selected by the preceding runs:
[serving[3]] [serving[4]] [serving[5]] +[tag[Vegetarian]] +[sort[title]]
This selects recipes for 3, 4 or 5 people, then filters those to keep only the vegetarian ones, and finally sorts any that are left into alphabetical order of title.
In a similar way, we can use a - sign to remove a run's tiddlers from the result so far. Here we select all vegetarian recipes apart from two:
[tag[Vegetarian]] -[title[ScrambledEggs]] -BeansOnToast