Who can tell me something about mathematics? . What's the difference between tolerance and real tolerance? .
Inclusion refers to including the same set as itself and its contained sets, such as {1, 2,3,4}, {1, 2,3,4}, {2,3,4} and so on {1, 2,3,4}. The difference between true inclusion and inclusion is that true inclusion does not contain the same set as itself, so true inclusion cannot contain {1, 2, 3, 4} in the set, and others can.