Package name amssymb
Usage \mathbb{}
Examples \mathbb{C}, \mathbb{R}
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Often used to represent space or transformation.
Package name mathrsfs
Usage \mathscr{}
Examples \ mathscr {x}, \ mathscr {y}, \ mathscr {a}
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This font is used in the set of all linear operators in functional analysis, so it should also be a conventional representation of space. Let's talk about it later. Leave it alone.
Package name amssymb
Usage \ Mathematics {}
Example \mathcal{L}
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This font is used for all compact operators.
Package name amssymb
Usage \mathfrak{}
Example \mathfrak{C}
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