👉 Tailband is a concept in mathematics, particularly in the field of linear algebra and numerical analysis. It refers to the region where a function or vector-valued function on a finite-dimensional real space is not differentiable at any point except at its endpoints. In other words, it means that if you try to differentiate this function along an axis, which is perpendicular to the direction of the function's derivative, and then extend that direction to infinity, the result will be zero. This kind of behavior is
