static S ai_matrixGet(S topic, S category) {
  if (has_verified(topic, "is", category)) ret "yes";
  if (has_verified(topic, "is not", category)) ret "no";
  if (has(topic, "is", category)) ret "yes [unverified]";
  if (has(topic, "is not", category)) ret "no [unverified]";
  
  try answer joinWithComma(ai_matrixUnpack(ai_texts_verified(topic, "$X", category)));
  S answer = joinWithComma(ai_matrixUnpack(ai_texts(topic, "$X", category)));
  if (nempty(answer)) answer += " [unverified]";
  ret answer;
}