Question: Radisson Blu Hotel is operated by a hotel company that is a subsidiary of what group?

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Radisson Blu Hotel Hamburg: Radisson Blu Hotel Hamburg is a 4-star superior hotel in Hamburg, Germany.  It is operated by Radisson Hotels & Resorts under the Radisson Blu brand.  At 108 meters height, it is the tallest hotel in Hamburg and the second tallest building in the city.  It has 32 floors and 556 rooms.  The hotel is surrounded by the park Planten un Blomen and situated directly next to the Congress Center Hamburg (CCH).  Hamburg Dammtor station is also located nearby.

Carlson Rezidor Hotel Group: Carlson Rezidor Hotel Group is one of the world’s largest hotel companies and includes 1,440 hotels in operation and under development with more than 230,000 rooms and a footprint spanning 115 countries and territories.  The Carlson Rezidor portfolio includes many global brands: Quorvus Collection, Radisson Blu, Radisson, Radisson RED, Park Plaza, Park Inn by Radisson and Country Inns & Suites By CarlsonSM.  The company offers a loyalty scheme called Club CarlsonSM, which offers various rewards at their hotels.  Over 95,000 people are employed in Carlson Rezidor Hotel Group hotel systems and the company is headquartered in Minneapolis, Singapore, and Brussels.

Radisson Blu: Radisson Blu (formerly Radisson SAS) is an upscale international chain of full service hotels and resorts brand for Radisson Hotels mostly outside the United States, including those in Europe, Africa, and Asia.  These are operated by Carlson Rezidor Hotel Group.  As of December 2014, Radisson Blu has 287 hotels operating throughout the world with 68,270 rooms, and 102 hotels under development with an additional 23,489 rooms.

Radisson Blu City Centre: Radisson Blu City Centre Chennai is a 12-storied five-star hotel located in Egmore, Chennai, India.  It is the second Radisson Blu hotel in the city after the Radisson Blu Chennai hotel near Chennai airport.

Radisson Blu Hotel Shanghai New World: The Radisson Blu Hotel Shanghai New World, also known as Radisson Hotel Shanghai New World or Radisson New World Hotel, is a hotel located at 88 Nanjing Road West (南京路88号), across from People's Park, in Shanghai's Huangpu District, in China.

Radisson Blu Hotel, Bremen: Radisson Blu Hotel is a luxury hotel in Bremen, Germany, operated by Radisson Hotels.  Formerly the Hilton Bremen, it is located near Böttcherstraße, to the southwest of the Town Hall.

Radisson Blu Hotel, Yerevan: Radisson Blu Hotel (Armenian: Ռեդիսոն Բլու Հոթել Երևան ), is a 5-star superior luxury hotel in Yerevan, Armenia.  It is operated by Radisson Hotels under the Radisson Blu brand.  The hotel was originally opened in 2005 as the Golden Palace Yerevan.  However, the hotel had been entirely renovated and expanded between 2014 and 2016.  It was eventually reopened in July 2016 as the Radisson Blu Hotel, Yerevan.

Radisson Blu Iveria Hotel, Tbilisi: The Radisson Blu Iveria Hotel is a hotel in the city center of Tbilisi located on Rose Revolution Square.  The hotel was built in 1967 by the Soviet government as the premier luxury hotel of the Georgian Soviet Socialist Republic and was named Hotel Iveria after the ancient kingdom of Iveria.  As a result of the war in Abkhazia in 1992, the hotel became a refugee camp housing more than 800 refugees.  In 2004 the refugees were removed from the hotel and offered $7000 per room.  The dilapidated hotel was stripped down to its steel structural frame and completely rebuilt as a modern luxury business hotel, managed by the Radisson Hotels group.  It reopened in 2009 as the Radisson Blu Iveria Hotel.

Stockholm Waterfront: Stockholm Waterfront, also known as "Klara Hotell och Konferens" is a building for offices, conferences and hotels.  The building is located at Klarabergsviadukten in central Stockholm, at the place where Klara postterminal previously stood, overlooking Riddarfjärden.  The complex is built for three functions, called "Waterfront Building" (for offices), "Radisson Blu Stockholm Waterfront" (for hotel) and "Stockholm Waterfront" (for congresses).  Architect is the White arkitekter firm.  Radisson Blu operates the hotel and congress parts and was opened on January 20, 2011.

Radisson Hotels: Radisson Hotels is an international hotel company and a subsidiary of the Carlson Rezidor Hotel Group.  It operates the brands "Radisson", "Radisson blu", "Radisson RED" and "Park Inn by Radisson" with more than 990 locations in 73 countries.

Supporting paragraphs: Radisson Blu Hotel, Bremen Radisson Hotels
Answer: Carlson Rezidor Hotel Group