In mathematics, infinity is the conceptual expression of such a numberless number. It is often symbolized by the lemniscate (also known as the lemniscate of Bernoulli), which looks something like the numeral 8 written sideways (). This symbol for infinity was first used in the 1600s by the mathematician John Wallis.
An epic is a poem; most epics started as oral tales that were passed down from generation to generation (often in the form of songs), which is why they're poems. A legend and a myth are more similar, but a myth most often explains something about the universe. So while there might be a legend about a man who slayed all the dragons, a myth would be about the man who caused it to rain, or how humans were created. Those are the basics differences.
Legend, typically, is a short (mono-) episodic, traditional, highly ecotypified historicized narrative performed in a conversational mode, reflecting on a psychological level a symbolic representation of folk belief and collective experiences and serving as a reaffirmation of commonly held values of the group to whose tradition it belongs.