Question: Who wrote the theme song for a different world?

Disambiguated questions and answers:
context: Lewis appeared for the first five of the six-season run as Jaleesa Vinson (later Vinson–Taylor) from 1987 until 1992. Lewis co-wrote the theme song to "A Different World", with Bill Cosby and Stu Gardner, and co-performed the song for the first season. In "A Different World", Although her character was married to another of the main characters on the show, her character disappeared from "A Different World" without explanation, like Chuck Cunningham of "Happy Days". Lewis appeared in a special week-long segment of "A Different World" called the "Hillman College Reunion" airing on Nick at Nite, along with Lisa Bonet, Jasmine Guy, Kadeem Hardison, Darryl M. Bell, Cree Summer, and Sinbad. On her "Super Password" appearance in 1988, she was paired with "Dallas" star Ken Kercheval, not any of her co-stars.
question: Who from Richmond wrote the theme song for a different world?
short_answers: Stuart Gardner

Stu Gardner
wikipage: Dawnn Lewis

context: No context provided
question: Who from Philadelphia wrote the theme song for a different world?
short_answers: William Henry Cosby, Jr.

Bill Cosby

context: Dawnn Lewis was born in Brooklyn, New York City, to Carl and Joyce Lewis, who are of African-American and Guyanese descent, She began singing at the age of four and acting at eleven. 
question: Who from Brooklyn wrote the theme song for a different world?
short_answers: Dawnn Jewel Lewis

Dawnn Lewis
wikipage: Dawnn Lewis

Long answers:
knowledge: content: A Different World is an American sitcom (and a spin-off of The Cosby Show) television series that aired for six seasons on NBC from September 24, 1987 to July 9, 1993.
wikipage: A Different World

content: The theme song was co-written by Stu Gardner, Bill Cosby, and Dawnn Lewis – who was also a cast member.
wikipage: A Different World

content: Stuart Gardner is an American musician and composer.
wikipage: Stu Gardner

content: As of 2012, Gardner lives in Richmond, Virginia, with his wife Gloria.[
wikipage: Stu Gardner

content: William Henry Cosby Jr. (/ˈkɒzbi/; born July 12, 1937) is an American stand-up comedian, actor, and author. Cosby began his career as a stand-up comic at the hungry i nightclub in San Francisco during the 1960s.
wikipage: Bill Cosby

content: Cosby was born on July 12, 1937,[7] in Philadelphia, Pennsylvania.
wikipage: Bill Cosby

content: Dawnn Jewel Lewis[1][2] (born August 13, 1961) is an American actress. Lewis is best known for her role as Jaleesa Vinson–Taylor on the NBC television sitcom A Different World from the series beginning in 1987 until the end of its fifth season in 1992, in addition to being on the show; Lewis co–wrote the theme song.
wikipage: Dawnn Lewis

content: Dawnn Lewis was born on August 13, 1961[4][5][6] in Brooklyn, New York City, to Carl and Joyce Lewis, who are of African-American and Guyanese descent,[7] She began singing at the age of four and acting at eleven.
wikipage: Dawnn Lewis
long_answer: A Different World is an American sitcom television series, that was a spin-off of The Cosby Show, aired for six seasons on NBC from September 24, 1987 to July 9, 1993. The theme song was co-written by Stu Gardner, Bill Cosby, and Dawnn Lewis, who was an actress from Brooklyn who also played Jaleesa Vinson–Taylor on the show. Stuart Gardner is an American musician and composer from Richmond, Virginia. Bill Cosby is an American stand-up comedian, actor, and author from Philadelphia.