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Dotless i and j

  1. Nov 16, 2011 #1

    cepheid

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    I'm wondering how to get dotless i and j in LaTeX on the forums. For some reason, \i and \j don't work for this. I can use \imath and \jmath, and I can even get carets on them to represent unit vectors:

    [tex] \hat{\imath}, \hat{\jmath} [/tex]

    The only remaining problem is that I can't get them to be typeset in boldface and upright as vectors traditionally are. If I do this hack:

    [tex] \hat{\textbf{$\imath$}}, \hat{\textbf{$\jmath$}} [/tex]

    then I can get them boldface, but still not upright. I think that the glyphs for \imath and \jmath are inherently italicized and there is no way to change this. Any suggestions for the OCD among us?
     
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  3. Nov 16, 2011 #2

    robphy

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    From
    http://groups.google.com/group/math...roup/mathjax-users/browse_frm/month/2010-11?&
    MathJax can use unicode...

    [tex]\mbox{abcdefgh}\ \unicode{x0131}\unicode{x0237}\ \mbox{klmnopqrstuvwyz}[/tex]

    You could define a macro for \i and \j
    [itex]\def\i{\unicode{x0131}} \i [/itex] [itex]\def\j{\unicode{x0237}} \j [/itex] (right-click show source)

    then use it later
    [tex]\i i\mbox{i}[/tex] [tex]\j j\mbox{j}[/tex]
     
  4. Nov 16, 2011 #3

    cepheid

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    So, definitions that people make using \def are universal and permanent (or at least persist until some user gives the same macro a different definition)???

    In any case, it still doesn't work:

    [tex]\def\i{\unicode{x0131}} \hat{\mathbf{\i}} [/tex]
     
  5. Nov 16, 2011 #4

    robphy

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    How's this?

    [itex]\def\ihat{\hat{\unicode{x0131}\!\!\unicode{x0131}}} \ihat [/itex] [itex]\def\jhat{\hat{\unicode{x0237}\!\!\!\unicode{x0237}}} \jhat [/itex]

    [tex] 8\ihat + 6\jhat[/tex]

    I suspect your \defs are local to your post.
     
  6. Nov 16, 2011 #5

    cepheid

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    That's very interesting! I just read that \! inserts a small negative space. So you have two unicode dotless i's slightly overlapping each other to produce a thicker one. It's very clever. Why the extra space for the j? Why not:


    [itex]\def\jhat{\hat{\unicode{x0237}\!\!\unicode{x0237}}} \jhat [/itex]


    Ah. That's why. A line thickness problem.
     
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