The Java Language Specification, Third Edition

15.12.2 Compile-Time Step 2: Determine Method Signature EXPRESSIONS
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type declaration, For example, if T :> List and T :> List, simply intersecting
the sets ST(List) = {List, Collection, Object} and
ST(List) = {List), Collection, Object} would yield a set {Object},
and we would have lost track of the fact that T can safely be assumed to be a List.
In contrast, intersecting EST(List) = {List, Collection, Object} and
EST(List) = {List, Collection, Object} yields {List, Collection, Object}, which we will
eventually enable us to infer T = List as described below.
The erased candidate set for type parameter Tj , EC, is the intersection of all
the sets EST(U) for each U in U1 .. Uk. The minimal erased candidate set for Tj is
MEC = { V | V in EC, and for all W ≠ V in EC, it is not the case that W