On the higher-rank Askey-Wilson algebras

In the paper, a new algebra ${\mathcal A}(n)$, which is generated by an upper triangular generating matrix with triple relations, is introduced. It is shown that there exists an isomorphism between the algebra ${\mathcal A}(n)$ and the higher Askey-Wilson algebra ${\mathfrak{aw}}(n)$ introduced by Cramp\'{e}, Frappat et al. Furthermore, we establish a series of automorphisms of ${\mathcal A}(n),$ which satisfy braid group relations and coincide with those in ${\mathfrak{aw}}(n).$