讲座内容：

For each integer $n\ge 1$, the thagomizer matroid is the graphic matroid of the complete tripartite graph $K_{1,1,n}$ (with parts of sizes $1,1,n$); for $n\ge 2$, its full automorphism group is the hyperoctahedral group. We compute the Kazhdan--Lusztig polynomial and the inverse Kazhdan--Lusztig polynomial in the equivariant setting for this action, and we show that each coefficient is an honest representation with a multiplicity-free irreducible decomposition. Taking dimensions recovers the previously known nonequivariant thagomizer polynomials, and the coefficient formulas are naturally stated using the wreath product Frobenius characteristic for the hyperoctahedral group.