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Macaulay2Doc :: isDirectSum

isDirectSum -- whether something is a direct sum

Description

Works for modules, graded modules, etc. The components of the sum can be recovered with components. 
i1 : isDirectSum ZZ^6

o1 = false
 
i2 : F = ZZ^2 ++ ZZ^3

       5
o2 = ZZ

o2 : ZZ-module, free
 
i3 : isDirectSum F

o3 = true
 
i4 : components F

        2    3
o4 = {ZZ , ZZ }

o4 : List

Ways to use isDirectSum :

For the programmer

The object isDirectSum is a method function.