For citations:

Liu M., Dudin A.N. Detailed proof of ergodicity condition for the multi-server retrial queueing system with heterogeneous servers and phase type distribution of service. Proceedings of the Institute of Mathematics of the NAS of Belarus. 2026;34(1):118-124. https://doi.org/10.67268/1812-5093-2026-34-1-118-124. EDN: PBYKZA