However, in order to capture the abstract structure of common notation better, MathML provides several more specialized scripting elements. These elements can be used to place limits on large operators, or for placing accents and lines above or below the base. The rules for rendering accents differ from those for overscripts and underscripts, and this difference can be controlled with the accent and accentunder attributes, as described in the appropriate sections below. MathML also provides an element for attachment of tensor indices. Tensor indices are distinct from ordinary subscripts and superscripts in that they must align in vertical columns.
Tensor indices can also occur in prescript positions.
The subscriptshift attribute specifies the minimum amount to shift the baseline of subscript down. The superscriptshift attribute specifies the minimum amount to shift the baseline of superscript up. The subscriptshift attribute specifies the minimum amount to shift the baseline of subscript down. The superscriptshift attribute specifies the minimum amount to shift the baseline of superscript up. However, another important use is placing limits on certain large operators whose limits are traditionally displayed in the script positions even when rendered in display style.