1 | initial version |

Well, in Python, when you write

```
g[0] = x^2
```

this means that the element 0 in the list `g`

, which was initialized to `g_0`

, is replaced `x^2`

. The symbolic variable `g_0`

remains unchanged; simply it is no longer the element 0 of `g`

:

```
sage: g = list(var('g_%d' % i) for i in range(4))
sage: g
[g_0, g_1, g_2, g_3]
sage: g[0] = x^2
sage: g
[x^2, g_1, g_2, g_3]
sage: g_0
g_0
```

In particular, `g_0`

is still there in `d_00`

. If you want to replace it by `x^2`

, you have to run `d[0][0] [eU, 2, 0] = g[0]`

again:

```
sage: d[0][0] [eU, 2, 0] = g[0]
sage: d[0][0].display(eU)
d_00 = -x^2 dx/\dX
```

2 | No.2 Revision |

Well, in Python, when you write

```
g[0] = x^2
```

this means that the element 0 in the list `g`

, which was initialized to `g_0`

, is replaced by `x^2`

. The symbolic variable `g_0`

remains unchanged; simply it is no longer the element 0 of `g`

:

```
sage: g = list(var('g_%d' % i) for i in range(4))
sage: g
[g_0, g_1, g_2, g_3]
sage: g[0] = x^2
sage: g
[x^2, g_1, g_2, g_3]
sage: g_0
g_0
```

In particular, `g_0`

is still there in `d_00`

. If you want to replace it by `x^2`

, you have to run `d[0][0] [eU, 2, 0] = g[0]`

again:

```
sage: d[0][0] [eU, 2, 0] = g[0]
sage: d[0][0].display(eU)
d_00 = -x^2 dx/\dX
```

Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.