Let Q=(∙⇉∙) be the self-dual A~1 quiver with its two vertices exchanged by the contravariant involution, and write A~1u,v for the indicated vertex and edge signs. Let L be the Lefschetz motive, q a formal variable, and Jsd, Jχsd, and DTsd the motivic, numerical, and Donaldson--Thomas self-dual invariants. Generating-series conjecture for the self-dual A~1 quiver. In the situation above, the following identities should hold:
For A~1+,++ and A~1−,−−,
n=0∑∞J(n,n)sdqn/2=(1−q1/2)(1−q1/2L)(1−qL)1/2,
n=0∑∞Jχ(n,n)sdqn/2=(1−q1/2)3/2(1+q1/2)1/2,n=0∑∞DT(n,n)sdqn/2=(1+q1/2)3/2(1−q1/2)1/2.
For A~1+,+− and A~1−,+−, all three generating series are equal to
n=0∑∞J(n,n)sdqn/2=n=0∑∞Jχ(n,n)sdqn/2=n=0∑∞DT(n,n)sdqn/2=(1−q1/2)1/2(1+q1/2)1/2.
For A~1+,−− and A~1−,++,
n=0∑∞J(n,n)sdqn/2=(1−qL−1)1/2,
n=0∑∞Jχ(n,n)sdqn/2=n=0∑∞DT(n,n)sdqn/2=(1−q)1/2.
These identities are suggested by numerical computations for the two-arrow quiver; the supplied source gives no resolution status.