Ghatgpt 5-1上线啦！ 
 [Screenshot_2025-11-13-08-59-54-131_com.openai.chatgpt-edit] 
 [Screenshot_2025-11-13-09-00-17-723_com.openai.chatgpt-edit] 

Determine the least real number M such that the inequality |ab(a² - b²) + bc(b² - c²) + ca(c² - a²)| ≤ M(a² + b² + c²)² holds for all real numbers a, b and c. 

AUTO模型给出的思考时间，不知道降智否。