The phrase "
by operation of law" is a legal term that indicates that a right or liability has been created for a party, irrespective of the intent of that party, because it is dictated by existing legal principles. For example, if a person dies without a
will, his
heirs are determined by operation of law. Similarly, if a person marries or has a child after his or her will has been executed, the law writes this
pretermitted spouse or
pretermitted heir into the will if no provision for this situation was specifically included.
Adverse possession, in which title to land passes because non-owners have occupied it for a certain period of time, is another important right that vests by operation of law.