Specific representations of these mathematical objects called “spiders” are generators of a string diagram in ZX-calculus. Quantum circuits are represented using these objects in networks that can be described using Penrose notation. A multi-particle Hilbert space is constructed by applying an operation named for these objects that, when applied to spaces of dimensions m and n, produces one of dimension (-5[1])m times n. These objects can be divided into covariant and contravariant components. A generalization of trace on these objects called “contraction” applies (10[1])when an index appears as both a subscript and superscript in Einstein notation. (10[1])A product named for these objects is denoted by a times symbol (10[1])inside a circle. For 10 points, name these objects that correspond to multilinear (-5[1])maps and whose rank-2 representations are matrices. ■END■ (0[3])