What is the ruling on a female teacher's statement: "I will not absolve/forgive anyone who does the homework by copying from other students"? And is there any validity to her right in this, and is it permissible for a Muslim to say: "I will not absolve/forgive"?

The teacher's statement "I do not absolve..." means that she does not make it permissible for them to cheat, and there is no harm in this. The teacher has the right to prevent her students from cheating on assignments so that each student solves them individually. The intention is for the student to review their lessons, solidify their knowledge, and practice solving problems independently. This benefits the student and trains them, and it also helps the teacher determine each student's level. Students should obey the teacher in such matters.