Abstract
Let G be a finite group. The prime graph Γ(G) of G is defined as follows. The vertices of Γ(G) are the primes dividing the order of G and two distinct vertices p, p′ are joined by an edge if G has an element of order pp′. Let L=L n (2) or U n (2), where n≧17. We prove that L is quasirecognizable by prime graph, i.e. if G is a finite group such that Γ(G)=Γ(L), then G has a unique nonabelian composition factor isomorphic to L. As a consequence of our result we give a new proof for the recognition by element orders of L n (2). Also we conclude that the simple group U n (2) is quasirecognizable by element orders.
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Khosravi, B., Moradi, H. Quasirecognition by prime graph of finite simple groups L n (2) and U n (2). Acta Math Hung 132, 140–153 (2011). https://doi.org/10.1007/s10474-010-0053-3
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DOI: https://doi.org/10.1007/s10474-010-0053-3