1 | initial version |

The variables you are trying to use in `K`

are not in `R`

. To have them there define `R`

as a polynomial ring in your variables like:

```
k_vars = [ ["k_{}_{}".format(u,v) for v in (1..2)] for u in (1..2) ]
R = PolynomialRing(IntegerModRing(22), sum(k_vars,[]) )
K = matrix(R, k_vars)
```

2 | No.2 Revision |

The variables you are trying to use in `K`

are not in its ring `R`

. ~~To have them there ~~Also, it's better to avoid dealing with symbolic ring (i.e. defining variables via `var`

) whenever possible. A better way here is to define `R`

as a polynomial ring in your variables like:

```
k_vars = [ ["k_{}_{}".format(u,v) for v in (1..2)] for u in (1..2) ]
R = PolynomialRing(IntegerModRing(22), sum(k_vars,[]) )
K = matrix(R, k_vars)
```

3 | No.3 Revision |

The variables you are trying to use in `K`

are not in its ring `R`

. Also, it's better to avoid dealing with symbolic ring (i.e. defining variables via `var`

) whenever possible. A better way here is to define `R`

as a polynomial ring in your variables like:

```
k_vars = [ ["k_{}_{}".format(u,v) for v in (1..2)] for u in (1..2) ]
R = PolynomialRing(IntegerModRing(22), sum(k_vars,[]) )
R._latex_names = sum( [["k_{{{},{}}}".format(u,v) for v in (1..2)] for u in (1..2)], [] )
K = matrix(R, k_vars)
```

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