Example:
All Real Estate assets are either very large or located in central areas but not both. While no apartment is without air-conditioning, all air-conditioned Real Estate assets are very large.
Real Estate Assets that are located in central areas are not apartments.
Conclusion follows.
Real-estate assets = A, very large = B, located in a central area = C, apartment = D, air conditioning = E.
According to the premises, (A -> B/C), (no D -> ~E), which means (D -> E), and (A+E -> B).
The conclusion states (A + C -> ~D).
If (A+E -> B), and (D -> E), then (D -> B) (because D is a subgroup of A). And since (A -> B/C), that means every A that is not B but C cannot be D.
In other words:
If all air-conditioned real-estate assets are very large, and all apartments are air conditioned, then all apartments are very large (because apartments are a subgroup of real-estate assets). And since no real-estate asset can be both very large and located in a central area, then this RE asset cannot be very large, as it is in a central area and it cannot be both. As you have concluded that all apartments are very large and this RE asset cannot be very large, then it is not an apartment.
