Szegö's construction conjecture for tight multigraphs

Let $\Gamma=(V,E)$ be a $(d,\ell)$-tight multigraph, with $\ell<\frac{4d+2}{3}$. Let $K_2^{2k-\ell}$ denote the graph with two vertices and $2k-\ell$ parallel edges, and let a $d$-dimensional $k$-extension be the graph operation used in the conjecture. Szegö's conjecture. The graph $\Gamma$ can be constructed from $K_2^{2k-\ell}$ using $d$-dimensional $k$-extensions, with no more than $2d-\ell$ parallel edges created between any pair of vertices. This conjecture strengthens the Frank–Szegö construction theorem by imposing the stated bound on parallel edges for $(d,\ell)$-tight multigraphs in the indicated range of $\ell$; its resolution is not specified in the source.