I think a good way of defining competition in relation to Pokemon would be to compare it to competitive sports. In every competitive sport, there are things in common:
- Reciprocity: All variables of competition are kept constant EXCEPT the one in which is being tested - you are allowed to do everything that your opponent is allowed to do. An example would be the 100m sprint: the distance is the same, the track surface is the same, the air resistance is kept the same to a point where any difference is negligible, the only variable being tested is the athlete's ability to run faster than everyone else
- There are a set of rules and boundaries in which the game operates, for example you are not allowed to use your hands in football/soccer unless you're the goalkeeper in which case you're only allowed to do so in the goal-square, the ball cannot go out of bounds, etc etc.