質問  省略

回答  抜粋

  \documentclass{article}
  \begin{document}

  Inline math: $A_B + x_X = y_Y$

  Display math:
  \[
  \sum_{i=1}^{N} x_i = \frac{1}{2} m v_K^2
                                   % ↑↑↑↑↑  で「K」が下がってる
  \]

  Numbered equation:
  \begin{equation}
  A_{IJ} = \sum_{k=1}^{K} B_{IK} C_{KJ}
  \end{equation}


質問
  how to control Formula subscript with capital letter under latex

回答
  You're absolutely right to ask for clarification! It seems I got a bit carried away with the general concept of subscripts and missed the nuance in your question.

  You're asking specifically about how to control the vertical alignment of subscripts, especially when they are capital letters, as they can sometimes appear a bit too high or low.

  Here's a breakdown of how to fine-tune the positioning of your capital letter subscripts in LaTeX:

  1. Default Behavior:

  LaTeX usually does a good job of positioning subscripts, but sometimes the default placement might not be ideal, especially with certain fonts or when capital letters are involved.

  2. Fine-tuning with \vphantom: これも利用

  The Problem: Capital letters, particularly those with a "descender" (like G, J, P, Q, Y), can sometimes make the subscript appear lower than desired.

  The Solution: Use \vphantom to create an invisible box with the height of a capital letter. This helps LaTeX align the subscript consistently.

  コード スニペット

  x_{\vphantom{X}A}  % Aligns the subscript A with a capital X
  In this example, \vphantom{X} creates an invisible box with the height of the letter "X". This ensures that the subscript "A" is aligned as if it were next to an "X", providing a more consistent vertical position.

  3. Adjusting with \raisebox:

  For More Control: If \vphantom isn't enough, you can use \raisebox for more precise vertical adjustments.

  コード スニペット

  x_{\raisebox{-1pt}{A}} % Raises the subscript A by 1pt
  The first argument to \raisebox is the vertical shift (positive to raise, negative to lower).
  The second argument is the content to be shifted.
  4. Considering Font Choice:

  Font Matters: Different fonts can have different metrics (sizes and shapes of characters). This can affect how subscripts appear. If you're having trouble with subscript alignment, consider trying a different font.
  Example:

  コード スニペット

  \documentclass{article}
  \begin{document}

  Default: $x_A$, $x_G$  % Notice how G might look a bit lower

  Using \vphantom: $x_{\vphantom{X}A}$, $x_{\vphantom{X}G}$ % Better alignment

  Using \raisebox: $x_{\raisebox{-1pt}{A}}$, $x_{\raisebox{-1pt}{G}}$ % Fine-tuned alignment

  \end{document}
  Important Notes:

  Experiment: The best approach often involves some experimentation. Try different combinations of \vphantom and \raisebox to find what looks best for your specific case.
  Consistency: Aim for consistency in your subscript placement throughout your document.
  I hope this provides a more accurate and helpful answer to your question! Let me know if you have any further questions or specific examples you'd like to discuss.