A torus-invariant Weil divisor on a normal toric variety is an integral linear combination of the torus-invariant prime divisors. The torus-invariant prime divisors correspond to the rays. In this package, the rays are ordered and indexed by the nonnegative integers.
The first examples illustrates some torus-invariant Weil divisors on projective 2-space
i1 : PP2 = projectiveSpace 2;
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i2 : D1 = toricDivisor({2,-7,3},PP2)
o2 = 2*D - 7*D + 3*D
0 1 2
o2 : ToricDivisor on PP2
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i3 : D2 = 2*PP2_0 + 4*PP2_2
o3 = 2*D + 4*D
0 2
o3 : ToricDivisor on PP2
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i4 : D1+D2
o4 = 4*D - 7*D + 7*D
0 1 2
o4 : ToricDivisor on PP2
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i5 : D1-D2
o5 = - 7*D - D
1 2
o5 : ToricDivisor on PP2
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i6 : K = toricDivisor PP2
o6 = - D - D - D
0 1 2
o6 : ToricDivisor on PP2
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One can easily extract individual coefficients or the vector of coefficients
i7 : D1#0
o7 = 2
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i8 : D1#1
o8 = -7
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i9 : D1#2
o9 = 3
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i10 : vector D1
o10 = | 2 |
| -7 |
| 3 |
3
o10 : ZZ
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i11 : vector K
o11 = | -1 |
| -1 |
| -1 |
3
o11 : ZZ
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