Generators and Relations for the Group U₄(ℤ[1/√2, i])
Abstract
We give a presentation by generators and relations of the group U₄(ℤ[1/√2, i]) of unitary 4×4 matrices with entries in the ring ℤ[1/√2, i]. This is motivated by the problem of exact synthesis for the Clifford+T gate set in quantum computation.