It’s impossible to overstate the contributions of Alvin Ailey. He helped to popularize modern dance, revolutionized the participation of African Americans in the discipline and wound up one of the LGBTQ community’s most influential cultural contributors. Though Ailey passed from AIDS in 1989, the company that bears his name continues to blaze trails—and they lead back to Boston for three evenings of new and established works. What’s more, this year the company will preview its production by first visiting schools and community centers in four Boston neighborhoods to offer free public events that teach the choreography to “Revelations,” Ailey’s signature piece and an epic dance expression of the African American experience. (For registration and details on the events in Hyde Park, Mattapan, Roxbury and Dorchester, see website below.)