Algebraic structureIn mathematics, an algebraic structure consists of a nonempty set A (called the underlying set, carrier set or domain), a collection of operations on A (typically binary operations such as addition and multiplication), and a finite set of identities, known as axioms, that these operations must satisfy. An algebraic structure may be based on other algebraic structures with operations and axioms involving several structures.
Tube (structure)In structural engineering, the tube is a system where, to resist lateral loads (wind, seismic, impact), a building is designed to act like a hollow cylinder, cantilevered perpendicular to the ground. This system was introduced by Fazlur Rahman Khan while at the architectural firm Skidmore, Owings & Merrill (SOM), in their Chicago office. The first example of the tube's use is the 43-story Khan-designed DeWitt-Chestnut Apartment Building, since renamed Plaza on DeWitt, in Chicago, Illinois, finished in 1966.
Brick GothicBrick Gothic (Backsteingotik, Gotyk ceglany, Baksteengotiek) is a specific style of Gothic architecture common in Northeast and Central Europe especially in the regions in and around the Baltic Sea, which do not have resources of standing rock (though glacial boulders are sometimes available). The buildings are essentially built using bricks. Buildings classified as Brick Gothic (using a strict definition of the architectural style based on the geographic location) are found in Belgium (and the very north of France), Netherlands, Germany, Poland, Lithuania, Latvia, Estonia, Kaliningrad (former East Prussia), Denmark, Sweden and Finland.
