1 | initial version |

If `a`

lives in a polynomial ring rather than in the symbolic ring,
then `a[k]`

extracts the coefficient of `x^4`

of `a`

, regardless
of the degree of `a`

.

Example:

```
sage: x = polygen(ZZ)
sage: a = 2 + 3*x
sage: [a[k] for k in range(4)]
[2, 3, 0, 0]
```

2 | No.2 Revision |

If `a`

lives in a polynomial ring rather than in the symbolic ring,
then `a[k]`

extracts the coefficient of

of ~~x^4~~x^k`a`

, regardless
of the degree of `a`

.

Example:

```
sage: x = polygen(ZZ)
sage: a = 2 + 3*x
sage: [a[k] for k in range(4)]
[2, 3, 0, 0]
```

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