摘要
Let F be a field with |F| ≥ 3, Km be the set of all m × m (m ≥ 4) alternate matrices over F. The arithmetic distance of A, B ∈ Km is d(A, B) := rank(A - B). If d(A, B) = 2, then A and B are said to be adjacent. The diameter of Km is max{d(A, B) : A, B ∈ km}. Assume that φ : Km→Km is a map. We prove the following are equivalent: (a) φ is a diameter preserving surjection in both directions, (b) φ is both an adjacency preserving surjection and a diameter preserving map, (c) φ is a bijective map which preserves the arithmetic distance.
Let F be a field with |F| ≥ 3, Km be the set of all m × m (m ≥ 4) alternate matrices over F. The arithmetic distance of A, B ∈ Km is d(A, B) := rank(A - B). If d(A, B) = 2, then A and B are said to be adjacent. The diameter of Km is max{d(A, B) : A, B ∈ km}. Assume that φ : Km→Km is a map. We prove the following are equivalent: (a) φ is a diameter preserving surjection in both directions, (b) φ is both an adjacency preserving surjection and a diameter preserving map, (c) φ is a bijective map which preserves the arithmetic distance.
基金
Supported by National Natural Science Foundation of China (Grant No. 10671026)