O Tannenbaum the faithless maiden of the folk song. This was changed to ' (green) at some point in the 20th century, after the song had come to be associated with Christmas. The tune is an old folk tune attested in the 16th century. It is also known as the tune of "" and of "". Below is the tune with the original German lyrics of the first verse: <score vorbis="1"> » </score> The tune has also been used (as a contrafactum) to carry other texts on many occasions. Some notable uses include: O Tannenbaum "" (; "O fir tree", English: "O
Allen Tannenbaum thesis advisor Heisuke Hironaka at the Harvard University in 1976. Tannenbaum has done research in numerous areas including robust control, computer vision, and biomedical imaging, having almost 500 publications. He pioneered the field of robust control with the solution of the gain margin and phase margin problems using techniques from Nevanlinna–Pick interpolation theory, which was the first H-infinity type control problem solved. Tannenbaum used techniques from elliptic curves to show that the reachability does not imply pole assignability for systems defined over polynomial rings in two or more variables over an arbitrary field. He pioneered the use of partial differential