1, superscript: n represents the upper bound, which refers to the elements in a poset that are greater than or equal to all the elements in its subset.

2. Subscript: I stands for the lower limit. If a set of real numbers M has a real number S, so that any number in M is greater than S, then S is called a lower bound of M. ..

3.k starts from I and goes all the way to n, all of which add up. ∑ i can also be expressed as the sum of I, which is a variable.

4. The symbol ∑ stands for summation. The pronunciation of ∑ is sigma, which means sum and summation in English. The method of sigma summation is called Sigma Notation.

Extended data:

1, superscript is generally used to further explain the marked words or paragraphs, so it is often used to explain the meaning, or the source, and its explanation is generally at the corresponding number at the bottom of the page or at the end of the book, and the correct writing of some symbols should also be marked.

2. Subscript, also known as the bottom corner mark, is a number, letter or other symbol appearing at the bottom of a normal font, which is especially used to describe formulas, mathematical expressions or compounds, such as the number "2" in the molecular formula "H2O" of water.

3. Capital σ is used for mathematical summation symbols, such as ∑Pi, where i= 1, 2, ..., t, which is the sum ...+angle of P 1+P2+. Lowercase σ is used for statistical standard deviation. Both the с of Cyrillic alphabet and the S of Latin alphabet are derived from Sigma.

References:

Baidu Encyclopedia _ ∑? Baidu Encyclopedia _ superscript? Baidu encyclopedia _ Subscript