The consent of one who “possesses common authority over premises or effects is valid as against the absent, nonconsenting person with whom that authority is shared.” United States v. Matlock, 415 U.S. 164, 170 (1974). Common authority has already been established. Ms. Fallsbauer was present at the apartment. David Fallsbauer was not present at the apartment. Since he was not there but his mother was, it was perfectly acceptable for her to grant consent. She has control over the premises so her consent to the search is valid against the nonconsenting absent person, David, simply because he was not