1 ×M 2 , x ik ∈ℝN ×K x i j 1 j 2 k =x i j 1 j 2 x ik =∑ l 1 =1 N ∑ l 2 =1 M 1 ∑ l 3 =1 M 2 ∑ l 4 =1 K G(l 1 l 2 l 3 l 4 )u l 1i u l 2 j 1 u l 3 j 2 u l 4 k または x j 1 j 2 k =∑ i=1 N x i j 1 j 2 k =∑ l 1 =1 M 1 ∑ l 2 =1 M 2 ∑ l 3 =1 K G(l 1 l 2 l 3 )u l 1 j 1 u l 2 j 2 u l 3 k u l 1 l 2 i =∑j 1 =1 M 1 ∑j 2 =1 M 2 u l 1 j 1 u l 1 j 2 x i j 1 j 2 ,u l 3 i =∑k=1 K u l 3 k x ik N M 1 N K N M 2 K N L N L K M 2 N M 1 M 2 M 1 K M 1 M 2 K M 1 M 2 L L L