Досліджено коректність задачі з двоточковими умовами за часовою змінною $t$ та умовами періодичності за просторовими координатами $x_1,\ldots,x_p$ для лінійних безтипних рівнянь із частинними похідними. Встановлено умови існування та єдиності розв'язку розглядуваної задачі у просторах експоненційного типу на торі. Доведено теореми про оцінки знизу послідовності характеристичних визначників задачі.

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