The problems, their groups and metaproperties

This study starts with the definition of problem; the problem is the difference between the current state and the target state. Based on the definition, three problem-solving approaches are made geometrically, i.e., current to target, target to current and mutual approach of current and target states. Further study is done on the approach from current to target states, and it is found that five problem groups exist. Most problems in the world fall into one of five problem groups, and the problems in each group follow identical problem-solving principles of the group. The authors suggest that these groups and problem-solving principles are the meta-properties of problems which overlook most of the problems in the world.