Examples of groups Projective semilinear group Let 𝑉 be a vector space over 𝕂. The projective semilinear group PΓL(𝑉) is the semidirect product group PΓL(𝑉)=Aut(𝕂)⋉PGL(𝑉) where PGL(𝑉) is the projective general linear group acted on by 𝜎 ∈Aut(𝕂) coördinatewise, so 𝜎[𝐴]𝜎−1[𝐱] =[𝜎(𝐴)][𝐱]. By the Fundamental theorem of projective geometry this forms the collineätion group of the projectivization P(𝑉). develop | en | SemBr