A vector space (also called a linear space) is a set of objects called "vectors", which may be added together and multiplied ("scaled") by numbers, called "scalars". Scalars are often taken to be real numbers, but there are also vector spaces with scalar multiplication by complex numbers, rational numbers, or generally any field. The operations of vector addition and scalar multiplication must satisfy certain requirements, called vector "axioms" (listed below in ). To specify that the scalars are real or complex numbers, the terms real vector space and complex vector space are often used.