Semimodules over semirings with idempotent addition.
Main publications:
S. N. Sergeev. Algorithmic Complexity of a Problem of Idempotent Convex Geometry // Mathematical Notes 74:6 (2003) 848–852.
S. Sergeev. Idempotent closures of definite matrices // Doklady Akademii Nauk, 408:4 (2006) 453–454 (in Russian).
S. Sergeev. Max-plus definite matrix closures and their eigenspaces // Linear Algebra and Its Applications, 421 (2007) 182–201.
P. Butkovic, H. Schneider, S. Sergeev. Generators, extremals and bases of max cones // Linear Algebra and Its Applications, 421 (2007) 394–406.
S. Gaubert, S. Sergeev. Cyclic projectors and separation theorems in idempotent semimodules// Fundamental'naya i Prikladnaya Matematika, 13:4 (2007) 31–52 (in Russian). E-print arXiv: math/0706.3347 (in English).
S. Gaubert, S. N. Sergeev, “Cyclic projectors and separation theorems in idempotent convex geometry”, Fundam. Prikl. Mat., 13:4 (2007), 31–52; J. Math. Sci., 155:6 (2008), 815–829
S. N. Sergeev, “Algorithmic Complexity of a Problem of Idempotent Convex Geometry”, Mat. Zametki, 74:6 (2003), 896–901; Math. Notes, 74:6 (2003), 848–852