I have a problem using \Aboxed
in the following align*
-environment:
\begin{align*}
\omega(\sigma_{ij}) &\equiv 1 - \left(\frac{27J_3}{2\sigma_e^3}\right)^2 \\
& = \omega(L) = 1 - \frac{\left( 9L - L^3\right)^2}{\left(L^2+3\right)^3}.
\end{align*}
I want to use \Aboxed
to put the last part of the final equation in a box, i.e.
\begin{align*}
\omega(\sigma_{ij}) &\equiv 1 - \left(\frac{27J_3}{2\sigma_e^3}\right)^2 \\
& = \Aboxed{ \omega(L) = 1 - \frac{\left( 9L - L^3\right)^2}{\left(L^2+3\right)^3}. }
\end{align*}
This gives me the error message in the title. However, using \Aboxed
in the upper equation of the align*
doesn't cause any problems at all. I've also used \Aboxed
in the last equation of other align*
's and align
's in my document. What causes the error in this case?
Best Answer
\Aboxed
(Frommathtools
) is designed to put a box across an alignment point (Refermathtools
documentation, section- 3.4.5, page 18). Hence,works. The
\Aboxed
command is defined as (frommathtools.sty
)Hence, when you use
\Aboxed
, TeX will greedily look for an&
(alignment character) and when it is not found, an error is returned.If you want a box only for a portion without an alignment point inside, you can use
boxed
(basically fromamsmath
andmathtools
loadsamsmath
also) asThe
boxed
command is defined as (fromamsmath.sty
)which does not have any concern for the alignment character
&
. (Hence it will not work across&
.)Conclusion: If you want a box to cross through an alignment point, use
\Aboxed
. On the other hand, if the box is for only a portion without alignment point, use\boxed
Complete MWE will be: