P () indicates the probability of occurrence in parentheses, and aδ b is the symmetry difference between sets A and B, that is, the set of elements belonging to one set but not to the other. It can be expressed as A△B=(A-B)U(B-A), so what does P(A△B) mean? Probability of symmetry difference between a and b.

Extended data:

If the experiment is repeated many times (denoted by X), the accidental event (denoted by A) appears many times (denoted by Y). Take X as the denominator and Y as the numerator to form a numerical value (denoted by P). In many experiments, P is relatively stable at a certain value, and P is called the probability of a certain occurrence.

The symmetry difference between sets a and b is usually expressed as an example of aδ b:

The symmetry difference between sets {1, 2,3} and {3,4} is {1, 2,4}. The symmetry difference between the set of all students and the set of all women is the set of all male students and all female non-students.

References:

Baidu Encyclopedia-Symmetrical Differences

Baidu encyclopedia-probability