### Fix handling of 1 in trivial identities for rational operators.

Especially, 1&f and 1:f were mistakenly always reduced to f, which is
incorrect when f accept the empty word.

* src/ltlast/multop.cc: Here.
* src/ltltest/equals.test: Add more tests.
 ... ... @@ -692,7 +692,7 @@ $b_1$, $b_2$ are assumed to be Boolean formul\ae. \end{align*} \noindent The following rules are all valid with the two arguments swapped. The following rules are all valid with the two arguments swapped (on input). %(Even for the non-commutative operators \samp{$\CONCAT$} and %\samp{$\FUSION$}.) ... ... @@ -705,10 +705,14 @@ The following rules are all valid with the two arguments swapped. \0\OR f &\equiv f & \0 \FUSION f &\equiv \0 & \0 \CONCAT f &\equiv \0 \\ \1\AND f &\equiv f& \1\ANDALT f &\equiv f & \1\OR f &\equiv \1 & \1 \FUSION f & \equiv f\\ \1\AND f&\equiv \begin{cases} 1 &\mathrlap{\text{if~} \varepsilon\VDash f} \\ f &\mathrlap{\text{if~} \varepsilon\nVDash f} \\ \end{cases} & \1\ANDALT b &\equiv b & \1\OR b &\equiv \1 & \1 \FUSION f & \equiv f\mathrlap{\text{~if~}\varepsilon\nVDash f}\\ \eword\AND f &\equiv f & \eword\ANDALT f &\equiv \begin{cases} ... ...