Steenrod algebras report additive order of 0 is p

[boothby]

This is wrong:

sage: S2 = SteenrodAlgebra(2)
sage: z = S2(0)
sage: z.additive_order()
2

looking at the code, it's easy to see why this happens...

    def additive_order(self):
        """
        The additive order of any element of the mod p Steenrod algebra is p.

        OUTPUT:
            order -- positive prime number

        EXAMPLES:
            sage: z = Sq(4) + Sq(6) + Sq(0)
            sage: z.additive_order()
            2
        """
        return self._prime

Component: algebra

Issue created by migration from https://trac.sagemath.org/ticket/5061

[boothby]

Attachment: 5061-steenrod-ao.patch.gz

[robertwb]

comment:4

Looks good. The documentation should probably be fixed as well though, and you need a doctest.