Opened 5 years ago

## #23312 new defect

# documentation and implementation disagree for BooleanPolynomialRing constructor

Reported by: | msaaltink | Owned by: | |
---|---|---|---|

Priority: | trivial | Milestone: | sage-8.0 |

Component: | algebra | Keywords: | |

Cc: | Merged in: | ||

Authors: | Reviewers: | ||

Report Upstream: | N/A | Work issues: | |

Branch: | Commit: | ||

Dependencies: | Stopgaps: |

### Description

sage: BooleanPolynomialRing? Signature: BooleanPolynomialRing(n=None, names=None, order='lex') Docstring: Construct a boolean polynomial ring with the following parameters: INPUT: * "n" -- number of variables (an integer > 1) * "names" -- names of ring variables, may be a string or list/tuple of strings * "order" -- term order (default: lex)

So we need `n > 1`

. And the error message for `n=0`

agrees:

sage: B = BooleanPolynomialRing(0) [...] ValueError: Number of variables must be greater than 1.

However, the implementation allows `n=1`

:

sage: B = BooleanPolynomialRing(1) sage: B Boolean PolynomialRing in None

and even negative `n`

:

sage: B = BooleanPolynomialRing(-2) sage: B Boolean PolynomialRing in None

The `n=1`

case appears to work fine, so I do not know why it is called out in the documentation. The 'n<0' cases must be a missing error check in the code.

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