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Macaulay2Doc :: eulers(Ring)

eulers(Ring) -- list the sectional Euler characteristics

Synopsis

Description

Computes a list of the successive sectional Euler characteristics of a ring (sheaf of), the i-th entry in the list being the Euler characteristic of the i-th generic hyperplane restriction of R
i1 : S = ZZ/101[a,b,c];
i2 : I = ideal(a^3+b^3+c^3)

            3    3    3
o2 = ideal(a  + b  + c )

o2 : Ideal of S
i3 : R = S/I

o3 = R

o3 : QuotientRing
i4 : eulers(R)

o4 = {0, 3}

o4 : List
i5 : J = substitute(ideal(b,a+c),R)

o5 = ideal (b, a + c)

o5 : Ideal of R
i6 : eulers(R/J)

o6 = {1}

o6 : List

See also