As additional retrieval limitation, we force the number of facts per answer candidate to be the same, in order to avoid a frequency bias for an answer candidate that appears more often in the knowledge source.
if we select the maximum 100 facts for each task instance and we have 10 answer candidates a i=1..10 , we retrieve the top 10 facts for each candidate a i that has either a subject or an object lemma for a token in a i .