Verbal warning based on student complaints without evidence and investigation I am working as a lecturer at a university. My students hate math and stats. Due to that, they hate my class. There is a group of students who are always shouting, yelling, and showing disrespectful behavior. This includes:

Dr., I will not let you give us the lesson, till you show us our marks (yelling).
Who are you to give us these regulations (yelling)?
Waving their hand, showing disrespectful emotional language.
Sending shouting, disrespectful, and bad behavior emails.

I took my evidence and showed them to my boss. No actions were taken against the students (the students still show disrespectful behavior). I spoke to the dean, but she was very biased against me. She said that these students are still young. Also, these students are very rich and used to have home services at their home, so they look at you like this. I was so angry and told that this is not acceptable at all. later, my boss' secretary, send me an email:

Tomorrow you will have a meeting with Dr. X and Dr. Y at &quot;time&quot;.

End of the email. I had no idea about that meeting and was not asked if this time was suitable for me or not. Last semester, Dr. X told me, while shouting and pointing her finger at my face, &quot;You are zero and will be zero forever, in my eyes&quot;. Also, &quot;You are bad raising women&quot;. No action was taken from my dean or head of the college.
I went to the meeting, their emotion was so bad. Sometimes, they used signal emotion with me. Which is disrespectful behavior.
At the meeting, without listening to me, or even showing me anything, the dean said:
&quot;I have a verbal warning for you&quot;.
I was so much shocked and asked why. She responded to me that,
&quot;Some students complain about your communication with them&quot;.
I said, could you please show me their complaints? Did you ask me, whether this is true or not?
Did you investigate the cases? You present the verbal warning and want me to sign it for no evidence. Then, I said, how about my complaints against these students with my clear evidence?
She said, in response to me, hold on, do not shout. I was not shouting at all. I felt unfair behavior from them. Then, I said if you will keep going with this, then I need to show this to the court as this is not the first time. She then said I will remove this verbal warning at all.
Now, I would like to write a minute for our meeting and send it back to them. My questions are:

Can the dean or the head, show, or process a warning report to any employee without evidence?
How can we describe their behavior against me?
Is it a good idea to write a minute?
Your question does not specify where in the world you are, but the behaviour you are describing from the students and staff sounds extreme.  It also sounds like your boss perceives you to be the cause of the problem and it sounds like they are not treating you well.  In such a case, your future at this institution might not be a good one, and it might be a good idea to consider looking for a position elsewhere.  Before you get to that point, I will make a couple of suggestions for what you might do here.
As a starting point, it might be useful to invite another academic to attend your lectures to observe what is going on.  Choose someone you respect as a good lecturer who has a good relationship with you, and ask them if they wouldn't mind coming along to a few of your lectures to observe.  This would have three purposes: (1) to see if you are doing anything wrong that would provoke such extreme behaviour; (2) in the event that you are not doing anything wrong, to act as a witness of what is occurring from the students; and (3) to give you advice on how you can improve your class (either by improving your own methods, or improving student discipline, or both).  The presence of another lecturer might alter the behaviour being observed, which is unfortunate, but even in that case the observer will be able to give you feedback on what you are doing.
Once you have had another lecturer observe your class you will be in a better position to determine whether you are contributing to the problems from your students, or whether these are just unruly students who are behaving badly without provocation.  You might also be in a better position to engage with your boss in relation to the problem.  (For example, you might now have another lecturer who can come along to meetings and give their observations of your class.)  Depending on what country you are in, there may be some rules for unfair disciplinary action or unfair dismissal.
Your proposal to write a minute and send it back to your boss might be okay, but only if the minute is written in an objective manner.  If the minute is just your characterisation of the way you were treated then it is unlikely that your boss will consider it an accurate statement of the meeting, and it might just further inflame the situation.