Module theory MOC

Direct sum of modules

The direct sum β¨π‘–βˆˆπΌπ‘‰π‘– of (right) modules (𝑉𝑖)π‘–βˆˆπΌ over 𝑅 is their coproduct in π‘…π–¬π—ˆπ–½. linalg It may be constructed as tuples with componentwise addition.

Internal direct sum

𝑉 is the direct sum β¨π‘–βˆˆπΌπ‘†π‘– iff every 𝑣 βˆˆπ‘‰ may be written as the sum of finitely many 𝑣𝑖 βˆˆπ‘†π‘– in precisely one way.

See also


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