Infrared Duality in Unoriented Pseudo del Pezzo

We study the orientifold projections of the $\mathcal{N}=1$ superconformal field theories describing D3-branes probing the Pseudo del Pezzo singularities PdP$_{3b}$ and PdP$_{3c}$. The PdP$_{3c}$ parent theory admits two inequivalent orientifolds. Exploiting $a$ maximization, we find that one of the two has an $a$-charge smaller than what one would expect from the orientifold projection, which suggests that the theory flows to the fixed point in the infrared. Surprisingly, the value of $a$ coincides with the charge of the unoriented PdP$_{3b}$ and we interpret this as the sign of an infrared duality.