The use of /mi/ does not seem infelicitous in a nominative context at first glance. If /mi/ acquired nominative case in the syntax, it would seem appropriate to use it. However, /aj/ is specified for the feature [+nom], and therefore must block the use of /mi/ in a nominative context. This is known as the Maximal Subset Condition or the Elsewhere Principle: if two items have a similar set of features, the one that is more specific will win. Illustrated in logical notation: