Direct Sum of Rings
Given a finite family of rings R1, ..., Rn, the direct product of the Ri is sometimes called the direct sum.
Note that in the category of commutative rings, the direct sum is not the coproduct. Instead, the coproduct is the tensor product of rings.
Read more about this topic: Direct Sum
Famous quotes containing the words direct, sum and/or rings:
“Forty years after a battle it is easy for a noncombatant to reason about how it ought to have been fought. It is another thing personally and under fire to have to direct the fighting while involved in the obscuring smoke of it.”
—Herman Melville (1819–1891)
“To help, to continually help and share, that is the sum of all knowledge; that is the meaning of art.”
—Eleonora Duse (1859–1924)
“If a man do not erect in this age his own tomb ere he dies, he shall live no longer in monument than the bell rings and the widow weeps.”
—William Shakespeare (1564–1616)