at="formula in ::formula.children track by formula.id" ng-if="$index == 1" ng-include="'formula-renderer.html'"></span>
        </span>
        <span ng-switch-when="imply">
            <span ng-repeat="formula in ::formula.children track by formula.id" ng-if="$index == 0" ng-include="'formula-renderer.html'"></span>
            <span data-drop="true" data-jqyoui-options jqyoui-droppable="{onDrop:'onDropFormula(::formula)'}" ng-model="dropped">-></span>
            <span ng-repeat="formula in ::formula.chil