1

Let $X$ be a chain complex augmented over $\mathbf{Z}$ with augmentation $\varepsilon_X:X_0 \to \mathbf{Z}$. We define $[1](X)$ to be the $\mathbf{Z}$-augmented chain complex such that $[1](X)_0 = \mathbf{Z}^2$ (on a basis $p_0,p_1$), and such that $[1](X)_{k+1}=X_k$ for all $k$. The augmentation map $\varepsilon_{[1](X)}:[1](X)_0\to \mathbf{Z}$ sends the basis elements $p_0,p_1$ to $1\in \mathbf{Z}$. For the boundary map $\partial:[1](X)_1 \to [1](X)_0$, we let $\partial(a)=\varepsilon_X(a)(p_1-p_0)$. For all other boundary maps, we let $\partial:[1](X)_{k+2} \to [1](X)_{k+1}$ be the map $\partial:X_{k+1} \to X_k$.

This functor $[1](-)$, the two-point suspension, gives an initial-object preserving functor $P:\mathbf{AugCh}\to ([1](0)\downarrow \mathbf{AugCh})$.

Then my question: Is the functor $[1](-)$ a "parametric left adjoint"? That is, is the functor $P$ a left adjoint? If this is the case, is there any explicit way to to construct the right adjoint in terms of chain complexes?

flag

Your Answer

Get an OpenID
or

Browse other questions tagged or ask your own question.