\frametitle{Linear algebra over finite fields (Magma)} How does the complexity of linear algebra over $\FF_{\ell}$ vary with $\ell$? A sensible behavior is exhibited by Magma 2.21-11: \pause \begin{verbatim} > C := ModularSymbols(100001, 2, -1); > M := HeckeOperator(C, 2); > M2 := Matrix(GF(2), M); time Rank(M2); 9047 Time: 1.710 > M3 := Matrix(GF(3), M); time Rank(M3); 9085 Time: 4.220 > p := 2^30 - 35; > Mp := Matrix(GF(p), M); time Rank(Mp); 9091 Time: 17.160 \end{verbatim}