psi -- cotangent line class

Synopsis

• Usage:

  psi_i

• Inputs:
  • i, an integer
• Outputs:
  • a ring element

Description

Here is a simple example which calculates $\int_{{\bar M}_{1,1}} \psi_1$.

i1 : R = hodgeRing (1, 1);

i2 : psi_1

o2 = psi
        1

o2 : R

i3 : integral(1, 1, psi_1)
warning: clearing value of symbol tempCh to allow access to subscripted variables based on it
       : debug with expression   debug 1257   or with command line option   --debug 1257

      1
o3 = --
     24

o3 : R

References

[AC] Arbarello, E. and Cornalba, M. Combinatorial and algebro-geometric cohomology classes on the moduli spaces of curves. J. Algebraic Geom. 5. (1996), no. 4, 705--749.

See also

• HodgeIntegrals -- Hodge integrals on the moduli space of curves
• hodgeRing -- create a ring containing algebraic classes on moduli spaces of curves
• integral -- evaluate Hodge integrals