} else if(tag.equals(MathExpressionEntityRef.TAG)) {
express = new MathExpressionEntityRef(element,
cf.getChildContext(MathExpressionEntityRef.GROUP));
} else if(tag.equals(MathExpressionGeneric.TAG)) {
express = new MathExpressionGeneric(element,
cf.getChildContext(MathExpressionGeneric.GROUP));
} else if(tag.equals(MathExpressionConditionBinary.TAG)) {
express = new MathExpressionConditionBinary(element,
cf.getChildContext(MathExpressionConditionBinary.GROUP));