Final answer:
The elements of a legally valid inter vivos gift as defined in the court case In re Estate of Piper.
Step-by-step explanation:
In the court case In re Estate of Piper, the court identified the elements of a legally valid inter vivos gift. These elements include: the donor's present intention to make a gift, acceptance by the donee, and effective delivery of the property to the donee. However, a written instrument excluding the property from the donor's will is not one of the elements required for a valid inter vivos gift.