In this paper new equalities between two different convolution products in cancellative naturally ordered semigroups (but not in groups) are given. We also give several applications in particular cases \documentclass[12pt]{minimal}
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\begin{document}${\Bbb N}^*$\end{document} and \documentclass[12pt]{minimal}
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\begin{document}${\Bbb R}^{+*}.$\end{document}