A single $3$-graph with infinite stability number

The stability number of a forbidden family measures how many different structures are needed to approximate all near-extremal constructions avoiding it. An infinite stability number means that no finite list of structures suffices. We construct a simple explicit $3$-graph whose stability number is infinite. This extends the infinite-stability phenomenon for finite forbidden families, established by Hou–Li–Liu–Mubayi–Zhang, to the single-forbidden setting, and further develops the single-$3$-graph direction of Balogh–Clemen–Luo, in which exponentially many exact extremal constructions coexist with stability.