Contact Coupling

A contact

1, no contact;

2, dotted line contact;

3, contact surface;

4, the intersection of contact;

 

Second, the coupling

 

 

Third, communication

1, the communication protocol

2, the communication session

3, the communication control

 

Fourth, explain the collection

1, no intersection

2, the intersection point

3, line intersection

4, personally set

5, includes

 

V. category theory to explain