In order to overcome such issues we assume that the sum of the parameters within each set of interactions is equal to zero.
ɪn ˈɔːɹdɚ tʊ ˌoʊvɚkˈʌm sˈʌtʃ ˈɪʃuːz wiː ɐsˈuːm ðætðə sˈʌm ʌvðə pɚɹˈæmɪɾɚz wɪðˌɪn ˈiːtʃ sˈɛt ʌv ˌɪntɚɹˈækʃənz ɪz ˈiːkwəl tə zˈiəɹoʊ.