Latex format collection

1 Left-align formulas within braces:

2 Cursive letters: \mathcal{}

3 Underscore: \_

4 Upper and lower limit multi-condition newline symbols: \atop

5 Multi-line formula equal sign alignment:

6 argmin/argmax subscript format:

7 The subscript position of the summation symbol:

(1) Place the symbol in a horizontal position

(2) Place it below the symbol