(a) Under this subchapter, proceedings shall in nature be in rem, and insofar as the rights of the purchaser are concerned, it shall be immaterial that the ownership of the lots, blocks, or parcels of land is incorrectly alleged in the proceedings.
(b) The decree shall be enforceable only against the delinquent property and not against any other property or estate of the defendants or the true owners of the delinquent property.
(c) In listing the lots, blocks, and parcels of land, they may be combined where they are constituent parts of a single improvement.