-- -*- M2-comint -*- hash: 2142737732895802609

i1 : S = ZZ/101[a,b,c]

o1 = S

o1 : PolynomialRing

i2 : mm = ideal vars S

o2 = ideal (a, b, c)

o2 : Ideal of S

i3 : M = S^1/(mm^2)

o3 = cokernel | a2 ab ac b2 bc c2 |

                            1
o3 : S-module, quotient of S

i4 : F = res M

      1      6      8      3
o4 = S  <-- S  <-- S  <-- S  <-- 0
                                  
     0      1      2      3      4

o4 : ChainComplex

i5 : sumBetti = sum(4,i->rank F_i)

o5 = 18

i6 : sumTor = sum(4,i->length(Tor_i(M,M)))

o6 = 50

i7 : chi2 F == eulerCharacteristic sym2 F-eulerCharacteristic wedge2 F

o7 = true

i8 : 2^(codim M)*(length M) == chi2 F

o8 = false

i9 : sumTor - chi2 F

o9 = 56

i10 : sumBetti*(length M) - sumTor

o10 = 22

i11 : excess M

o11 = (6, 12, 22)

o11 : Sequence

i12 : 
