Strictly speaking, del is not a specific operator, but rather a convenient mathematical notation for those three operators, that makes many equations easier to write and remember. The del symbol can be interpreted as a vector of partial derivative operators, and its three possible meanings—gradient, divergence, and curl—can be formally viewed as the product with a scalar, dot product, and cross product, respectively, of the del "operator" with the field. These formal products do not necessarily commute with other operators or products.
A deel (Mongolian:дээл[teːɮ]; Buryat: дэгэл) is an item of traditional clothing commonly worn since centuries ago among the Mongols and other nomadic tribes of Central Asia, including various Turkic peoples, and can be made from cotton, silk, wool, or brocade.
The deel is still commonly worn by both men and women outside major towns, especially by herders. In urban areas, deels are mostly only worn by elderly people, or on festive occasions. The deel appears similar to a caftan or an old European folded tunic. Deels typically reach to below the wearer's knees and fan out at the bottom and are commonly blue, olive, or burgundy, though there are deels in a variety of other colors.
The deel looks like a large overcoat when not worn. Instead of buttoning together in the middle, the sides are pulled against the wearers body, the right flap close to the body with the left covering. On the right side of the wearer are typically 5 or 6 clasps to hold the top flap in place. There is one clasp below the armpit, three at the shoulder, and either one or two at the neckline.
Leonardo is a 2.5 foot social robot, the first created by the Personal Robots Group of the Massachusetts Institute of Technology. Its development is credited to Cynthia Breazeal. The body is by Stan Winston Studios, leaders in animatronics. Its body was completed in 2002. It was the most complex robot the studio had ever attempted as of 2001. Other contributors to the project include NevenVision, Inc., Toyota, NASA’s Lyndon B. Johnson Space Center, and the Navy Research Lab. It was created to facilitate the study of human–robot interaction and collaboration. A DARPA Mobile Autonomous Robot Software (MARS) grant, Office of Naval Research Young Investigators Program grant, Digital Life, and Things that Think consortia have partially funded the project. The MIT Media Lab Robotic Life Group, who also studied Robonaut 1, set out to create a more sophisticated social-robot in Leonardo. They gave Leonardo a different visual tracking system and programs based on infant psychology that they hope will make for better human-robot collaboration. One of the goals of the project was to make it possible for untrained humans to interact with and teach the robot much more quickly with fewer repetitions. Leonardo was awarded a spot in Wired Magazine’s 50 Best Robots Ever list in 2006.