.
Hence any two abstractive classes which satisfy the condition
cover each other. Hence every class which satisfies the condition
is covered by every other class which satisfies the same condition
. That is to say, every such class is a
.
Hence any two abstractive classes which satisfy the condition
cover each other. Hence every class which satisfies the condition
is covered by every other class which satisfies the same condition
. That is to say, every such class is a