Homotopy group with coefficients

In topology, a branch of mathematics, for $i\; \backslash ge\; 2$, the i-th homotopy group with coefficients in an abelian group G of a based space X is the pointed set of homotopy classes of based maps from the Moore space of type $(G,\; i)$ to X, and is denoted by $\backslash pi\_i(X;\; G)$.{{harvnb|Weibel|2013|loc=Ch. IV. Definition 2.1}} For $i\; \backslash ge\; 3$, $\backslash pi\_i(X;\; G)$ is a group. The groups $\backslash pi\_i(X;\; \backslash Z)$ are the usual homotopy groups of X.