Some of New York’s legit unions, including IATSE Local One and the American Guild of Variety Artists, are squaring off in a territory dispute with the producers of “Empire,” a variety show performed in a tent erected in the theater district.Producers haven’t negotiated deals with Gotham’s cadre of stage labor orgs, spurring union members to picket where “Empire” performs. At 440 seats, the circus/cabaret/burlesque show falls under the category of an Off Broadway production. Both Local One, the legit stagehands org, and AGVA, the union that also negotiates contracts for New York’s Cirque du Soleil and Rockettes productions, said in interviews that producers of “Empire” had abruptly stopped communicating with the unions following a round of initial inquiries and discussions. In a joint statement, “Empire” producers Ross Mollison and David J. Foster seemed to dig in their heels against the union pushback. “We are thrilled to be bringing a circus tent to the heart of midtown, but to be clear: This is not a Broadway show, the tent is not a Broadway house, and we don’t charge Broadway prices,” they said. Enions plan to continue picketing until producers respond.