 The Duffin–Kemmer–Petiau equation (DKP equation, also called "Duffin–Kemmer equation" or "Kemmer equation") plays a role in the description of the standard model of particles, together with the Yang-Mills field.The Duffin–Kemmer–Petiau equation is closely linked to the Proca equation and the Klein–Gordon equation.The DKP equation suffers the same drawback as the Klein–Gordon equation in that it calls for negative probabilities.