  The new item is \(\mathcal{E}\), an evidence  function, which originated in (Mkrtychev 1997). This maps  justification terms and formulas to sets of worlds. The intuitive  idea is, if the possible world \(\Gamma\)  is in  \(\mathcal{E} ( t , X)\), then \(t\) is  relevant or admissible evidence for \(X\) at  world \(\Gamma\) . One should not think of relevant evidence as  conclusive. Rather, think of it as more like evidence that can be  admitted in a court of law: this testimony, this document is  something a jury should examine, something that is pertinent, but  something whose truth-determining status is yet to be considered.  Evidence functions must meet certain conditions, but these are  discussed a bit later.