Ownership is the right to enjoy, dispose of, and recover a thing within legal limits. Incidental rights include possession, use, fruits, and the right to exclude others. Disposal rights cover destruction, abuse, alienation, transformation, and encumbrance. Recovery actions include accion interdictal (summary action for possession), accion publiciana (plenary action for possession based on ownership), and accion reivindicatoria (plenary action for ownership). The Supreme Court has affirmed that ownership implies the right to possession and that a Torrens titleholder is entitled to possession.

Limitations on ownership stem from specific laws (e.g., easements), the state's inherent powers (police power, taxation, eminent domain), conditions imposed by grantors (e.g., donations with conditions), inherent conflicts with other rights (e.g., nuisances), and limitations imposed by the owner themselves (e.g., leases, voluntary easements).

The doctrine of self-help allows owners to use necessary physical force to repel actual or threatened physical invasion, provided it is reasonable and immediate. The 'sic utere tuo ut alienum non laedas' principle dictates that one's use of property should not injure the rights of others, emphasizing fair use and consideration for neighbors. The doctrine of state of necessity (incomplete privilege) allows temporary interference with property to avert imminent and greater danger, highlighting that property is a social function, and owners must sometimes tolerate minor inconveniences for the greater good of others.

An owner of land owns the surface, everything under it, and can construct, plant, or excavate, subject to servitudes, special laws, and ordinances. This includes subsurface rights to resources like water. Aerial rights pertain to the space above the land, subject to regulations like those for aerial navigation, particularly near airports.

Hidden treasure is defined as any hidden, unknown deposit of money, jewelry, or other precious objects whose lawful ownership is unclear. Generally, hidden treasure belongs to the owner of the land where it's found. Exceptions apply if the finder is not the owner, in which case they share 50/50, provided the discovery was by chance on another's property, the state's property, or a political subdivision's property, and the finder is not a co-owner or trespasser. For married individuals, their share of hidden treasure is considered conjugal or community property.

Accession is the right by which the owner of a thing becomes the owner of everything it produces or that is inseparably united with it. Accession discreta refers to the owner of the principal also owning its fruits (natural, civil, and industrial). Exceptions exist for possessors in good faith, usufructuaries, lessees of rural lands, pledgees, and antichretic creditors, who may have rights to appropriate or apply the fruits under specific legal provisions.

Accession continua involves the attachment or production of something in relation to a principal thing. For real property, this includes industrial accession (building, planting, sowing) and natural accession (alluvium, avulsion, change of river course, formation of islands). Specific rules govern the obligations of landowners and material owners regarding construction, planting, or sowing, especially concerning good faith and bad faith, and the right to compensation or removal.

For personal property, accession continua includes: 'Adjunction' or 'Conjunction,' where two things belonging to different owners form a single object (e.g., a diamond set in a gold ring). 'Commixtion' or 'Confusion,' which refers to the mixture of solids or liquids, respectively, belonging to different owners. 'Specification,' which is the transformation of another's material by the application of labor into something new with different identity.

When a landowner uses materials of another, they must pay their value; if in bad faith, they must also pay damages. The material owner can remove their materials if it doesn't injure the work, or in any event if the landowner acted in bad faith, with right to indemnification. Articles 448 and 449 of the Civil Code address situations where a builder, planter, or sower (BPS) acts in good or bad faith on another's land. A BPS in bad faith loses everything without indemnity, except for necessary expenses for preservation. A lessee is not considered a BPS in bad faith.

Alluvium is the gradual and imperceptible increment of land along riverbanks due to the current; it belongs to the riparian owner and cannot be from human intervention or sea water. Avulsion is the sudden transfer of a known portion of land from one tenement to another by a river current. The original owner retains ownership of the avulsed portion but must remove it within two years. Unlike alluvium, avulsion involves identifiable land sections and gives the owner a period to reclaim their property.

When a river naturally changes course, the abandoned riverbed belongs to the owners of the property occupied by the river, in proportion to the area lost. If human intervention causes the change, these rules don't apply. Islands formed in the sea within territorial waters belong to the state; outside territorial waters, they belong to the first occupant. Islands in navigable or floatable rivers belong to the state. In non-navigable rivers, an island belongs to the owner of the nearer riverbank; if equidistant, it's divided between the owners of both banks.

Co-ownership is the right of common dominion where two or more persons have an undivided interest in a thing. Key characteristics include plurality of subjects, an undivided object, and recognition of ideal shares. Co-ownership can be created by donation, law (e.g., succession), occupation (possession by multiple persons), contract (e.g., sale), and chance (e.g., finding hidden treasure).

Co-owners have rights to use the common thing (with limitations), share in benefits, benefit from prescription even if not all possessed, alienate/sell/mortgage undivided interests (subject to agreements and rights of legal redemption by co-owners), and substitute others in enjoyment. Their obligations include sharing charges and preservation expenses proportionally. Co-ownership can be extinguished by consolidation or merger of shares, acquisitive prescription by a third person, loss or destruction of the property, partition (extrajudicially or judicially), expropriation by the state, termination of an agreed period, or sale of the property. The sale of the property by co-owners transfers ownership and ends the existing co-ownership, potentially creating a new one if multiple buyers acquire it.