I have 2 equations, both have to be numbered and aligned. Equations' numbers should be vertically centered. But equations are long and have to be broken into 2 or 3 lines each. It would be great to have 2 alignment points in each line. But I cannot achieve that using split
. Or can I? Here is the MWE:
\begin{align}
\begin{split}
z_1^{i,j}
& = a_1 \, x_1^{i,j} + b_1 \, \delta_1^{i,j} \\
& + \sum_k y_k^{i,j} \qquad \forall ~i,j
\end{split}
\\
\begin{split}
z_2^{i,j}
& = a_2 \, x_2^{i,j} + b_2 \, \delta_2^{i,j} + c_2 \\
& + z_1^{i,j} \qquad \forall ~i,j
\end{split}
\end{align}
Basically, I want the same output as produced with this code, especially equations' numbers vertically centered. In addition, I want \forall ~i,j
from both equations to be also aligned, i.e. below each other. Solution with alignat
instead align
would be even better for me.
Best Answer
I believe you're using a two column format.
The environment
split
only accepts one alignment point; you can use\mathmakebox
frommathtools
(that also loadsamsmath
) andcalc
:Note that
\,
between factors is not used, while^{}
is recommended in order to push subscripts at the same level. The+
on the second line shouldn't be under the equals sign, as it belongs to the right hand side of the expression.However, the subscripts are not really level, because of
j
at the exponent, so you might want a slightly more complex adjustment: