Compare the possible meanings
| Notation | Typical meaning | How to identify it |
|---|---|---|
eˣ | Euler's number as exponential base | Calculus |
eᵢ | Basis vector | Linear algebra |
e = y−ŷ | Error or residual | Statistics |
e∈E | Graph edge | Graph theory |
Examples
- d(eˣ)/dx=eˣ.
- The standard basis vector e₁=(1,0,…,0).
- A residual may be written eᵢ=yᵢ−ŷᵢ.
How to decide
Use the surrounding subject, subscripts, and explicit definitions to identify the role.
How to verify the interpretation
Check whether the expression requires a fixed constant or a variable object.