Русско-англо-русский юридический словарь

By contrast, a clause in a contract that provides that one party may terminate upon the occurrence of a "material breach" by the other party falls within the second category referred to above. Such a clause, however, leaves open the question of whether or not a particular breach is "material". (lexology.com)

And, as in the original story itself, the re-enactment is determined to leave open the question of who, if anyone, actually survives the apparent plunge down into the gorge. (BBC News)