tensor積の性質

$ (\pmb{a}\otimes\pmb{b})^\top=\pmb{b}\otimes\pmb{a}

$ (\pmb{a}\otimes\pmb{b})^{-1}=?

この変形は無理そう

$ (\pmb{a}\otimes\pmb{b})(\pmb{c}\otimes\pmb{d})=(\pmb{b}\cdot\pmb{c})(\pmb{a}\otimes\pmb{d})