20">Let F be a field of characteristic 0. In 2008 Etingof, Kim and Ma conjectured that 0fc7b17c" title="Click to view the MathML source">T(m)T(n)⊂T(m+n−1) if and only if m or n is odd. In 2010 Bapat and Jordan confirmed the “if” direction of the conjecture: if at least one of the numbers m, n is odd then 0fc7b17c" title="Click to view the MathML source">T(m)T(n)⊂T(m+n−1). The aim of the present note is to confirm the “only if” direction of the conjecture. We prove that if m=2m′ and n=2n′ are even then f456" title="Click to view the MathML source">T(m)T(n)⊈T(m+n−1). Our result is valid over any field F.