12 | | I think that the answers are consistent, for the following reason: |

13 | | * `H0.2*H0.3` is zero in the cohomology ''group'' H^2^(D8). As elements ~~in that group, they are~~ zero, hence "is_zero()" returns True. |

14 | | * However, even though the~~y vanish and thus represent a relation of the cohomology ring, they are still cocycles of degree 2. Thus, they are~~ not equal to `H0.zero_element()`, which is a cocycle of degree 2. Hence, the comparison with the zero of the cohomology ''ring'' returns False. |

| 12 | I think that the answers are consistent, for the following reasons: |

| 13 | * `H0.2*H0.3` is zero in the cohomology ''group'' H^2^(D8). As elements of that group, the product is zero, hence "is_zero()" returns True. |

| 14 | * However, even though the product vanishes and thus represents a relation of the cohomology ring, it still is a cocycle of degree 2. Thus, it is not equal to `H0.zero_element()`, which is a cocycle of degree 2. Hence, the comparison with the zero of the cohomology ''ring'' returns False. |