gnature-symbol">: </span><span class="tsd-signature-type">boolean</span><a href="#isFixed.isFixed-1" aria-label="Permalink" class="tsd-anchor-icon"><svg viewBox="0 0 24 24"><use href="../assets/icons.svg#icon-anchor"></use></svg></a></li><li class="tsd-description"><div class="tsd-comment tsd-typography"><p>This predicate returns true if the vertex should not be moved
by the layout algorithm but still have an effect on nearby and connected vertexes.
The default implementation returns <a href="ForceDirectedV