make facts like "mem_Collect_eq" more likely to be picked up by few-fact slices
make facts like "mem_Collect_eq" more likely to be picked up by few-fact slices

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle