# Usages of Unicode symbols


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`Julia` allows the use of *Unicode* symbols to replace variable names and for function calls. Unicode operations are entered in this pattern `\name[tab]`. That is a slash, `\`, the name (e.g., `alpha`), and then a press of the `tab` key.


In these notes, the following may appear as variable or function names


| `\Name`  | Symbol | Usage notes                     |
|:-------- |:------ |:------------------------------- |
| `\euler` | `ℯ`    | The variable `e`                |
| `\pi`    | `π`    |                                 |
| `\alpha` | `α`    |                                 |
| `\beta`  | `β`    |                                 |
| `\delta` | `δ`    |                                 |
| `\Delta` | `Δ`    | Change, as in `Δx`              |
| `\gamma` | `γ`    |                                 |
| `\phi`   | `ϕ`    |                                 |
| `\Phi`   | `Φ`    | Used for parameterized surfaces |
| `x\_1`   | `x₁`   | Subscripts                      |
| `r\vec`  | `r⃗`   | Vector annotation               |
| `T\hat`  | `T̂`   | Unit vector annotation          |


The following are associated with derivatives


| `\Name`    | Symbol | Usage notes                 |
|:---------- |:------ |:--------------------------- |
| `\partial` | `∂`    |                             |
| `\nabla`   | `∇`    | del operator in CwJ package |


The following are *infix* operators


| `\Name`  | Symbol | Usage notes   |
|:-------- |:------ |:------------- |
| `\circ`  | `∘`    | composition   |
| `\cdot`  | `⋅`    | dot product   |
| `\times` | `×`    | cross product |


Infix operators may need parentheses due to precedence rules. For example, to call a composition, one needs `(f ∘ g)(x)` so that composition happens before function evaluation (`g(x)`).