An analysis of each of these elements in both allegories will provide an interesting comparison. Dante uses allegory to relate the sinner's punishment to his sin, while Plato uses allegory to discuss ignorance and knowledge. Dante's Inferno describes the descent through Hell from the upper level of the opportunists to the most evil, the treacherous, on the lowest level. His allegorical poem describes a hierarchy of evil.
Symbolism is an essential element of both works.
In Plato's allegory symbols are used to represent truth, ignorance, society and the fear of change. Truth is represented by the sun, while ignorance is represented by the cave, its limited vision and darkness within. The prisoners represent ignorant members of society who are content to believe that what they see is all that exists. Fear of change is represented by the prisoners angry reaction towards the freed, enlightened prisoner. Dante's Inferno is a detailed description of sin and its relationship to degrees of punishment.