A system is designed to solve a complex problem (p_0) by first breaking it down into a series of n sub-problems (p_1 to p_n) and finding their respective answers (a_1 to a_n). The final answer to the original problem (a_0) is then generated in a concluding synthesis step, represented by the function a_0 = S_0(p_0, {p_<=n, a_<=n}). Based on this formula, which of the following sets of information is required by the synthesis function S_0 to produce the final answer a_0?

Diagnosing a Faulty Summarization System

Consider a system that solves a complex problem (p_0) by breaking it down into a series of sub-problems and their answers ({p_≤n, a_≤n}). According to the final answer synthesis formula, a_0 = S_0(p_0, {p_≤n, a_≤n}), the synthesis function S_0 could still produce a correct and complete final answer (a_0) if it were only provided with the set of sub-problem answers (a_≤n).