I'd like to render the string Id as a Math Operator in upright boldface. What is the proper markup for that? \mathbf{\operatorname{Id}}? \operatorname{mathbf{Id}}? \mathop{\mathbf{Id}}?

Note; this is for code in a macro, not inline.

  • 3
    \operatorname{\mathbf{Id}} – egreg Jun 27 at 15:06




$\mathbf{\operatorname{Id}}$ is wrong

$\operatorname{\mathbf{Id}}$ seems good

$\mathop{\mathbf{Id}}$ seems good

$\displaystyle\operatorname{\mathbf{Id}}_{X}$ seems good

$\displaystyle\mathop{\mathbf{Id}}_X$ is wrong


enter image description here

Thus the right one is \operatorname{\mathbf{Id}}. Of course, if you use it more than a couple of times, you should do


in your document preamble and use \Id.

  • This is for a macro, not inline. I've edited the question to clarify that. – shmuel Jun 27 at 18:18

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