What differentiates epic poetry and tragedy according to Aristotle's Poetics?

According to Aristotle, both tragedy and epic are forms of imitation. Tragedy imitates directly by means of mimesis and epic both directly and indirectly by means of mimesis and diegesis. While epic imitates solely by means of words, tragedy also imitates by means of spectacle. Both epic and tragedy portray people better or greater than the average spectator, unlike comedy which portrays people as worse than they actually are and uses humour to dissuade us from acting badly (Aristotle's lost treatise on comedy may be summarized in the Tractatus Coislinianus; see also Eco, The Name of the Rose for interesting view of Aristotle on comedy)

Due to practical constraints of production, tragedy ideally has a single unified action which is often restricted to a specific time and place. and a small n umber of characters, while epic has a broader scope of coverage.

What is an epic and why does Aristotle consider it inferior to tragedy in Poetics?

An epic is a long narrative poem that tells the story of a hero and the hero's deeds. The hero is often of noble birth, and their actions are of great significance to the culture or nation in which the story is set. Examples of epic poetry include Homer's Iliad and The Odyssey, Virgil's Aeneid, and Milton's Paradise Lost.

In his work Poetics, Aristotle argues that epic poetry is inferior to tragedy because it is less serious and less complete. According to Aristotle, tragedy is a more powerful art form because it deals with serious and important matters, such as human suffering and the downfall of noble characters. Tragedy also has a more complete narrative structure, with a clear beginning, middle, and end, while epic poetry can be more episodic in nature. Additionally, Aristotle believed that the characters in epic poetry are less complex and less fully developed than the characters in tragedy.