Is there a way to insert a blank line between two equations in align environment?
From what I understand a blank line is interpreted as \par and
\par is not allowed in align. Can I disable this "feature" in
align environment?
Reason:
I like my code to be in 80 column format. So when I hit M-q (fill-paragraph) without blank lines, the code looks like this:
\begin{align}
\min \sum_{k \in K} \sum_{(i,j) \in A} c_{ij} x_{ij}^k + \sum_{(i,j)
\in A} f_{ij} y_{ij} \\ \sum_{j \in V_i^+} x_{ij}^k - \sum_{j \in
V_i^-} x_{ji}^k = \begin{cases} d^k & \text{si } i = O(k) \\ -d^k
& \text{si } i = D(k) \\ 0 & \text{sinon} \end{cases} & \quad
\quad \forall i \in V, \; \forall k \in K \\ \sum_{k \in K} x_{ij}^k
\le u_{ij} y_{ij} & \quad \quad \forall (i,j) \in A
\end{align}
instead of this:
\begin{align}
\min \sum_{k \in K} \sum_{(i,j) \in A} c_{ij} x_{ij}^k + \sum_{(i,j)
\in A} f_{ij} y_{ij} \\
\sum_{j \in V_i^+} x_{ij}^k - \sum_{j \in V_i^-} x_{ji}^k
= \begin{cases} d^k & \text{si } i = O(k) \\ -d^k & \text{si } i =
D(k) \\ 0 & \text{sinon} \end{cases} & \quad \quad \forall i \in
V, \; \forall k \in K \\
\sum_{k \in K} x_{ij}^k \le u_{ij} y_{ij} & \quad \quad \forall
(i,j) \in A
\end{align}
which is easier (for me) to read and edit.
