Information:  - The Røa Line is a rapid transit line of the Oslo Metro, Norway, which runs from Majorstuen in Oslo to Østerås in Bærum. It serves neighborhoods such as Smestad, Hovseter, Huseby and Røa in northwestern Oslo, and Grini, Øvrevoll and Østerås in northeastern Bærum. The line is served by Line 2 of the metro, which connects to the city center via the Common Tunnel and onwards along the Furuset Line. The lowest part of the Røa Line, consisting of two stations, is shared with the Kolsås Line, and thus also served by Line 2 of the metro. The Røa Line is owned by Kollektivtransportproduksjon, and operated by Oslo T-banedrift on contract with the public transport agency Ruter.  - Oslo is the capital and the most populous city in Norway. It constitutes both a county and a municipality. Founded in the year 1040, and established as a "kaupstad" or trading place in 1048 by Harald Hardrada, the city was elevated to a bishopric in 1070 and a capital under Haakon V of Norway around 1300. Personal unions with Denmark from 1397 to 1523 and again from 1536 to 1814 and with Sweden from 1814 to 1905 reduced its influence. After being destroyed by a fire in 1624, the city was moved closer to Akershus Fortress during the reign of Christian IV of Denmark and renamed Christiania in his honour. It was established as a municipality ("formannskapsdistrikt") on 1 January 1838. Following a spelling reform, it was known as Kristiania from 1877 to 1925, at which time its original Norwegian name was restored.  - Bærum is a municipality in Akershus county, Norway. The administrative centre of the municipality is the town of Sandvika. Bærum was established as a municipality on 1 January 1838. A suburb of Oslo, Bærum is located on the west coast of the city.  - The Kolsås Line is line of the Oslo Metro. It branches off from the Røa Line at Smestad Station and runs through western Oslo and Bærum to Kolsås Station. It serves the neighborhoods of Ullernåsen, Øraker, Jar, Bekkestua, Haslum, Gjettum and Kolsås. It is served by Line 3 of the metro at a 15-minute headway. The section from Jar to Bekkestua is build as a dual system with overhead wires, allowing Line 13 of the Oslo Tramway to continue from the Lilleaker Line to Bekkestua every ten minutes.  - The Oslo Metro (or or simply ) is the rapid transit system of Oslo, Norway, operated by Sporveien T-banen on contract from the transit authority Ruter. The network consists of five lines that all run through the city centre, with a total length of , serving 101 stations of which 17 are underground or indoors. In addition to serving 14 out of the 15 boroughs of Oslo (all except St. Hanshaugen), two lines run to Bærum. In 2015, the system had an annual ridership of 94.4 million.  - Norway (; Norwegian: (Bokmål) or (Nynorsk); Sami: "Norgga"), officially the Kingdom of Norway, is a sovereign and unitary monarchy whose territory comprises the western portion of the Scandinavian Peninsula plus the island Jan Mayen and the archipelago of Svalbard. The Antarctic Peter I Island and the sub-Antarctic Bouvet Island are dependent territories and thus not considered part of the Kingdom. Norway also lays claim to a section of Antarctica known as Queen Maud Land. Until 1814, the Kingdom included the Faroe Islands (since 1035), Greenland (1261), and Iceland (1262). It also included Shetland and Orkney until 1468. It also included the following provinces, now in Sweden: Jämtland, Härjedalen and Bohuslän.  - The Common Tunnel, sometimes called the Common Line, is a long tunnel of the Oslo Metro which runs through the city center of Oslo, Norway. The name derives from the fact that all six lines of the metro use the tunnel, which runs from Majorstuen to Tøyen. The section has six stations, including the four busiest on the metro.  - Rapid transit, also known as heavy rail, metro, subway, tube, or underground, is a type of high-capacity public transport generally found in urban areas. Unlike buses or trams, rapid transit systems are electric railways that operate on an exclusive right-of-way, which cannot be accessed by pedestrians or other vehicles of any sort, and which is often grade separated in tunnels or on elevated railways.  - Ruter AS is the public transport authority for Oslo and Akershus counties in Norway. Formally a limited company  60% of the shares in which are owned by the Oslo county municipality and 40% by that of Akershus  it is responsible for administrating, funding, and marketing (but not operating) public transport in the two counties, including buses, the Oslo Metro ("T-banen i Oslo"), Oslo Trams ("Trikken i Oslo"), and ferry services. Ruter also holds agreements with the Norwegian State Railways concerning the regulation of fares on commuter train services operated within the two counties.  - Holmen is a station on the Røa Line ( line 2 ) of the Oslo T - bane system . It is located between Makrellbekken and Hovseter . The station is 6.1 km from Stortinget . Holmen was opened on 24 January 1935 when the line was completed to Røa . The station is at an altitude of 119.4 metres above sea level.The station is located in a mainly residential area . The Oslo subway system has fought a battle against graffiti , and one of the incidents turned violent on 2 February 2007 , when a subway driver was beaten by a vandal .  - Røa was a borough of the city of Oslo, Norway up to January 1, 2004, when it became part of the Vestre Aker district.  Røa is also a suburb of Oslo, located approximately 7 kilometers away from downtown Oslo. It primarily consists of duplex houses and apartment blocks as well as single-family detached homes. It also has a small shopping mall.  - Grini is a district in northeastern Bærum, Norway.  - The Furuset Line is a long line on the Oslo Metro between Hellerud and Ellingsrudåsen in Oslo, Norway. Running mostly underground, it passes through the southern part of Groruddalen, serving neighborhoods in the boroughs of Alna and Furuset. The line is served by Line 2 of the metro with four or eight trains per hour. The line is owned by Kollektivtransportproduksjon and operated by Oslo T-banedrift on contract with Ruter using MX3000 trains.    What is the relationship between 'holmen ' and 'vestre aker'?
The answer to this question is:
located in the administrative territorial entity