[v4.1.0] Alpha symbol position in subscript changes after upgrading from MathJax 2.7.4 to 4.1.0

[SpiceDeveloper]

Issue description
We recently upgraded MathJax from version 2.7.4 to version 4.1.0 in our web application. After the upgrade, we observed a visual change in the vertical position of the Greek letter \alpha when it appears inside a subscript.

The LaTeX expression is unchanged.

Observed behavior in MathJax 2.7.4
In MathJax 2.7.4, the alpha symbol is rendered fully inside the subscript area.

• The subscript (α/2) is clearly positioned below the base symbol t
• The alpha character aligns visually with the rest of the subscript
• The overall appearance looks balanced and consistent

Attached Screenshot of MathJax 2.7.4 output

Observed behavior in MathJax 4.1.0
In MathJax 4.1.0, the same expression renders differently.

• The alpha symbol inside the subscript is shifted upward
• Alpha appears much closer to the main symbol t
• The subscript looks visually misaligned compared to MathJax 2.7.4

Attached Screenshot of MathJax 4.1.0 output

Attached HTML file
Mathjax-4.1.0-math-alpha-symbol-display-issue.html

Key point

• No change in the LaTeX input
• Only the MathJax version changed to 4.1.0
• The issue is specifically the vertical position of \alpha inside subscripts

Summary

• MathJax 2.7.4: \alpha stays properly within the subscript
• MathJax 4.1.0: \alpha shifts upward toward the baseline
• This causes a visible difference in rendering for formulas containing alpha in subscripts

Question
Is this change in the positioning of \alpha inside subscripts expected behavior in MathJax 4?
OR
Is there a recommended way to achieve rendering similar to MathJax 2.7.4?

Please let us know the supported or recommended solution to achieve this behavior .

[dpvc]

This is not actually due to the alpha, but to the bevelled fraction (from \nicefrac I presume, though you don't give the TeX code that you are using). The v3/v4 output isn't properly handing the scaling of the vertical offset in scriptstyle and scriptscriptstyle.

I will make a PR to fix it in the next release. In the meantime, you can use the following configuration

  MathJax = {
    loader: {
      'output/chtml': {
        ready() {
          const {ChtmlMfrac} = MathJax._.output.chtml.Wrappers.mfrac;
          Object.assign(ChtmlMfrac.prototype, {
            _makeBevelled_: ChtmlMfrac.prototype.makeBevelled,
            makeBevelled(display) {
              this._makeBevelled_(display);
              const {u, v} = this.getBevelData(display);
              if (u) this.adaptor.setStyle(this.dom[0].childNodes[0], 'verticalAlign', this.em(u));
              if (v) this.adaptor.setStyle(this.dom[0].childNodes[2], 'verticalAlign', this.em(v));
            }
          });
        }
      }
    },
  }

to patch the bevelled fraction rendering.

[SpiceDeveloper]

Thanks for the detailed explanation and valuable suggestions..

I applied the suggested configuration workaround, and it resolves the alignment issue correctly on our side. Thank you also for offering to make a PR to address this in a future release — that’s very helpful.

Appreciate the quick support and guidance.