One co-proprietor can exercise no authority over the common property against the will of the other.

Explanation

(English-origin maxim.) No co-owner may exercise dominion over common property against the will of another co-owner — cite this to enjoin a partner or joint tenant from unilateral use, alteration, or disposition of shared property.

Where this applies

• One co-owner of a vacation home rents it out to tourists without the other co-owner's consent; the court orders the rentals to stop because no co-proprietor may exercise authority over shared property against the other's will.
• A joint tenant begins clearing trees on commonly held land over the other owner's objection; the court enjoins the activity because one co-owner cannot unilaterally alter shared property.
• Two siblings inherit a house equally; one wants to renovate and the other objects; the court holds that neither can proceed without the other's agreement.