FUNCTION: tauinv - inverse Auslander-Reiten-shift

CALLING SEQUENCE:
tauinv(f)

PARAMETERS:
f - an arbitrary class of type quiver

SYNOPSIS:

• Computes the inverse of the Auslander-Reiten shift of any object in K₀ X of type "quiver".

EXAMPLES:

> with(tubular):

> read_in(3,3,3);

assume f2 defined

> show(f2);

> f1 := tauinv(f2); show(f1);