TY - JOUR ID - Cho2021 LB - Cho2021 AU - Cho, Ilwoo AU - Jorgensen, Palle E.T. TI - Multi-variable quaternionic spectral analysis ST - Multi-variable quaternionic spectral analysis JO - Opuscula Math. JA - Opuscula Math. JF - Opuscula Mathematica PY - 2021 VL - 41 IS - 3 SP - 335 EP - 379 DO - https://doi.org/10.7494/OpMath.2021.41.3.335 UR - https://doi.org/10.7494/OpMath.2021.41.3.335 AB - In this paper, we consider finite dimensional vector spaces \(\mathbb{H}^n\) over the ring \(\mathbb{H}\) of all quaternions. In particular, we are interested in certain functions acting on \(\mathbb{H}^n\), and corresponding functional equations. Our main results show that (i) all quaternions of \(\mathbb{H}\) are classified by the spectra of their realizations under representation, (ii) all vectors of \(\mathbb{H}^n\) are classified by a canonical extended setting of (i), and (iii) the usual spectral analysis on the matricial ring \(M_n(\mathbb{C})\) of all \((n \times n)\)-matrices over the complex numbers \(\mathbb{C}\) has close connections with certain "non-linear" functional equations on \(\mathbb{H}^n\) up to the classification of (ii). KW - the quaternions \(\mathbb{H}\) KW - vector spaces \(\mathbb{H}^n\) over \(\mathbb{H}\) KW - \(q\)-spectral forms KW - \(q\)-spectral functions SN - 1232-9274 ER -