This is the 5294th most frequent Russian word.
омские
"Омские" translates to "Omsk's" or "related to Omsk," referring to something or someone from Omsk, a city in Russia.
Here, 'омские' acts as an adjective describing 'streets', indicating that these streets are associated with the city of Omsk.
Омские улицы зимой покрыты снегом.
The streets of Omsk are covered with snow in winter.
In this sentence, 'омские' describes 'pryaniki' (gingerbread), specifying their origin from Omsk.
Я купил омские пряники в подарок.
I bought Omsk gingerbread as a gift.
Here, 'омские' qualifies 'mathematicians', implying that these mathematicians are from Omsk.