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# Journal of Operator Theory

Volume 64, Issue 2, Fall 2010  pp. 453-468.

Summary:  To any complex Hadamard matrix $H$ one associates a spin model commuting square, and therefore a hyperfinite subfactor. The standard invariant of this subfactor captures certain "group-like" symmetries of $H$. To gain some insight, we compute the first few relative commutants of such subfactors for Hadamard matrices of small dimensions. Also, we show that subfactors arising from Dita--Haagerup type matrices have intermediate subfactors, and thus their standard invariants have some extra structure besides the Jones projections.