Before revision:  Our algorithm converges robustly and exactly to the correct backpropagation gradients, requires only a single type of neuron , utilises only a single backwards phase, and can perform credit assignment on arbitrary computation graphs.
After revision:  Our algorithm converges robustly and exactly to the correct backpropagation gradients, requires only a single type of computational unit , utilises only a single backwards phase, and can perform credit assignment on arbitrary computation graphs.