A matrix whose entries are all integers. Special cases which arise frequently are those having only (-1, 1) as entries (e.g., Hadamard matrix), (0, 1)-matrices having only (0, 1) as entries (e.g., adjacency matrix, Frobenius-König theorem, Gale-Ryser theorem, Hadamard's maximum determinant problem, hard square entropy constant, identity matrix, incidence matrix, Lam's problem), and those having (-1, 0, 1) as entries (e.g., alternating sign matrix, C-matrix). The zero matrix could be considered a degenerate case of an integer matrix. Integer matrices are sometimes also called "integral matrices, " although this usage should be deprecated due to its confusing use of the term "integral" as an adjective.

(0, 1)-matrix | (-1, 0, 1)-matrix | (-1, 1)-matrix | alternating sign matrix | C-matrix | complex matrix | fifteen theorem | Frobenius-König theorem | Gale-Ryser theorem | Hadamard matrix | Hadamard's maximum determinant problem | Hafner-Sarnak-McCurley constant | hard square entropy constant | identity matrix | incidence matrix | integer-matrix form | interspersion | Lam's problem | mortal | mortality problem | real matrix | Smith normal form | special matrix | unit matrix | zero matrix