Max Cost Records is can't Delete by using Triggers....

trigger trigger4 on Empl__c (before delete) {
    if(trigger.isBefore){
       if(trigger.isDelete){
           List< Empl__c> emp=[select  Cost__C from  Empl__c all rows];
           for(Empl__C val:emp){
               for(Empl__c val1:trigger.old){
                    if(val.cost__C > val1.cost__C){
                        if(val.cost__c== val1.cost__c){
                          val1.adderror('u cant delere');
                        }
                      
                    }              
               }
              
           }
       }
    }
}