The second is the symmetry of mathematical propositions, such as four forms of propositions, dual propositions, etc.
Third, mathematical concepts are symmetrical, such as addition, subtraction, multiplication and division, power sum root, intersection and union.
Fourth, the mathematical form is symmetrical, such as: the root formula of quadratic equation and the inductive formula of trigonometric function;
5. Symmetry of mathematical methods, such as induction and deduction; Synthesis and analysis, etc.
Sixth, the mathematical structure is symmetrical, such as commutative law, associative law, Goldbach conjecture (1+ 1) and so on.