I am trying to understand, in general, how laws apply to the use of violence between two individuals, when the circumstances of the use of violence was one of continuous escalation. I invite and welcome any corrections to my terminology or to any of my possibly incorrect base assumptions. I am not considering a specific jurisdiction, rather, I am very interested in how different jurisdictions handle this matter. I do believe that is on topic for Law.SE.
Consider two people having a verbal argument. I would like to assume for purposes of discussion that the option of just walking away is not available - perhaps the setting is a train. Two people yelling at each other have yet to transgress any laws in most jurisdictions, correct? Now A makes a gesture. Now B makes a defensive gesture, that could be interpreted as a threatening gesture. Now A yells in B's ear. Now B pushes A further away from his ear. Now A pushes B. Now B punches.
Clearly B has clearly transgressed. At what point did either A or B perform an initial transgression, that the law would see fit to deal with? Where is the line drawn? Let us call this event N.
Now, the point of contention that I would like to understand is would event N still be considered an aggression, if event N-1 was repeated many times. That is, do any jurisdictions consider an event that is not in itself a transgression, to be a transgression if performed multiple times? Is there a legal term for such actions?