(Eve Online)Fleet structure

Fleet in Eve is not just a group of ships. Things are much more complicated – firstly, a fleet is usually divided into two groups - the core, and support ships. Secondly, the fleet is much stronger then a group of ordinary ships because all the ships in the fleet are specialized. And thirdly, the leading ship of the fleet can give various bonuses to the accompanying ships. This is achieved by installing special modules on the bonus distributing ship.
The division of the fleet into groups is understandable and based on the general separation of the ships by the damage they do. Capital ships and battleships smash the enemy, and at this time brisk frigates and destroyers cover the former with their rapid fire and movement. Such a fleet is already balanced, and it cannot be won in any case by a stronger group (to a reasonable extent) of even capital ships.
Specialization of the ships in the fleet gives even more benefits than just arranging the fleet of different ships with different combat characteristics. There are certain roles in the fleet, which players specialize in. The player must like that kind of role, and has to want to play it. Due to specialization, he/she can manage a specialized ship. Such vehicles are usually good at one thing, instead are noticeably worse than the "average" vehicle in other specialties. It's bad for a solo flight, but here we consider the case of the fleet - then you are not alone, and your fellow pilots are the always near. Thus the disadvantages of your specialization are compensated by their specializations. The main thing is that they exists, the specialized vehicles in your fleet :) - tacklers, which are better than any others in locking targets; damagers, specializing in damage; commanders exercising general control; tanks, taking the fire upon themselves; scouts / covert ops - invisible ships; and many others. A fleet, in which the roles are clearly separated, is much stronger than a group made up of random ships, and will always beat the latter.