As used in this subchapter and in subchapters III, V and VIII of this chapter:
If any property is owned, leased or subleased by the taxpayer in common with any other person or persons, such property may constitute "qualified property" only to the extent of the taxpayer's proportionate interest.
For purposes of this paragraph, "control," with respect to a corporation, means ownership, directly or indirectly, of stock possessing 50 percent or more of the total combined voting power of all classes of the stock of such corporation entitled to vote and 50 percent or more of the total number of shares of all other classes of such corporation's stock; "control," with respect to a trust, means ownership, directly or indirectly, of 50 percent or more of the beneficial interest in the principal or income of such trust. The ownership of stock in a corporation, of a capital or profits interest in a partnership or association or of a beneficial interest in a trust shall be determined in accordance with the rules for constructive ownership of stock provided in § 267(c) of the Internal Revenue Code ( 26 U.S.C. § 267(c) ) other than paragraph (c)(3) of such section.
30 Del. C. § 2010