"问题公式化" can be translated into English as "formulate the problem" or "problem formulation" (as a noun phrase).
"Formulate the problem" is a verb phrase, emphasizing the action of expressing or defining a problem in a clear, structured, or mathematical way.
"Problem formulation" is a noun phrase, referring to the process or result of expressing a problem in a specific, often formal, manner.
Both expressions are commonly used in academic, technical, or problem-solving contexts.