Logical relationship is an abstract summary of various causal relationships in production and life. If there are multiple conditions that determine whether an event F occurs (or is established), it can be represented by a, b, c, etc. There is a causal relationship between whether event F occurs and whether conditions A, B and C are established.

Basic logical relationship:

1, and logical AND gate: If all conditions A and B that determine an event F must be met, the event F will occur, otherwise it will not. This logical relationship is called AND logic.

2. OR logical AND OR gate: If at least one of the conditions A and B for determining event F is met, event F will occur, otherwise it will not. This logical relationship is called OR logic.