Fastest-possible PoW via Simple DAG

The discussion revolves around the analysis of different methodologies applicable within the context of a Proof of Work (PoW) Directed Acyclic Graph (DAG) blockchain network, focusing on how network topology and latency between nodes can significantly impact the fairness and efficiency of block creation among miners. A particular method that initially seemed promising involves adjusting to the hashrate-weighted latency among peers within the network. However, this approach may inadvertently benefit larger miners due to their potential for lower latency connections with each other, thereby skewing the distribution of block rewards in their favor. This phenomenon would ultimately undermine the equitable distribution of rewards across participants of varying scales.

In contrast to the aforementioned method, an alternative strategy known as the "Nc/Nb" method is introduced, characterized by its robustness against changes in the network's topology. This technique does not rely on time or timestamps but instead focuses on measuring the "width" of the DAG. The width is determined by examining recent ancestors within the chain to gauge a measurement. The essence of this method lies in its ability to adjust the "block time" to be a direct multiple or fraction of the network's latency, thus circumventing the issues associated with variable latencies among miners. The formula provided for adjustment, D = mean_D_ancestors * (1 - width_measured/N + width_desired/N), where D represents difficulty, employs an Exponential Moving Average (EMA) to smooth out fluctuations, ensuring a more stable and fair approach to block difficulty adjustments based on the observed and desired width of the DAG.

This discussion highlights the complexities and challenges inherent in designing equitable mechanisms for PoW DAG chains, emphasizing the need for innovative solutions like Braidpool that aim to mitigate the disadvantages faced by smaller miners due to network topology changes.