Orthogonal Functions by G. Sansone Covers expansion in a series of orthogonal functions and preliminary notions of Hilbert space; expansion in Fourier series and in series of Legendre polynomials and spherical harmonics; expansions in Laguerre and Hermite series.
Problems in Euclidean Space: Application of Convexity by H. G. Eggleston This study of convex sets in real Euclidean spaces of 2 or 3 dimensions illustrates the different ways in which convexity can enter into the formulation as the solution. 1957 edition.
Projective Geometry and Projective Metrics by Herbert Busemann, Paul J. Kelly This text examines the 3 classical geometries and their relationship to general geometric structures, with particular focus on affine geometry, projective metrics, non-Euclidean geometry, and spatial geometry. 1953 edition.
Theory of Groups of Finite Order by W. Burnside Classic introduction to group theory covers permutation; composition-series of groups; isomorphism; Abelian groups; groups whose orders are the powers of primes; Sylow's theorem; permutation groups; groups of linear substitutions; more.
