wiː kæn jˈuːz ɐɡˈɛn ðə fˈækt ðˈæt, ɪf ɪz stˈeɪbəl ˈɔːl ɪts ˈaɪdʒənvˌæljuːz hæv nˈɛɡətˌɪv ɹˈiːəl pˈɑːɹt tə ʃˈoʊ ðæt ɪz juːnˈiːk.
We can use again the fact that, if  is stable (all its eigenvalues have negative real part) to show that  is unique.