In Sage 9.6.rc3, the interior product of a named vector field with a named 1-form resulting in zero yields an error:

sage: M = Manifold(2, 'M')
sage: X.<x, y> = M.chart()
sage: v = X.frame()[0]    # vector field d/dx
sage: f = X.coframe()[1]  # 1-form dy
sage: v.interior_product(f)
...
ValueError: the name of an immutable element cannot be changed

This is because set_name is called on M.zero_scalar_field(), while it should not.

CC: @mjungmath @tscrim

Component: manifolds

Keywords: interior_product, set_name

Author: Eric Gourgoulhon

Branch/Commit: 960e0ed

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/33780