| 1 | This ticket fixes several problems related to the conversion of derivatives to and from sympy: |

| 2 | |

| 3 | - the derivative arguments were permuted when converting to sympy (comment:7) |

| 4 | - the conversion from Sage to sympy did not account for the case of variables with multiple occurences (comment:1) |

| 5 | - the first argument of the derivative was skipped when converting from sympy (comment:6) |

| 6 | - sympy returns arguments of type `sympy.core.containers.Tuple` which was not handled |

| 7 | - Sage's derivative does not accept tuples, so the arguments must be flattened |

| 8 | - sympy's derivative count is converted to rationals, so Sage's derivative must accept rational arguments |

| 9 | |

| 10 | (Original description below.) |

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| 12 | ------ |

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