Cyclic cohomology of certain nuclear Fr\'echet and DF algebras

We give explicit formulae for the continuous Hochschild and cyclic homology and cohomology of certain topological algebras. To this end we show that, for a continuous morphism $\varphi :\text{X}\to \text{Y}$ of complexes of complete nuclear $DF$-spaces, the isomorphism of cohomology groups $H^n(\phi): H^n(\X) \to H^n(\Y)$ is automatically topological. The continuous cyclic-type homology and cohomology are described up to topological isomorphism for the following classes of biprojective $\widehat{\otimes }$-algebras: the tensor algebra $E \hat{\otimes} F$generatedbytheduality$(E, F, < \cdot, \cdot >)$ for nuclear Fr'echet spaces $E$ and $F$ or for nuclear $DF$-spaces $E$ and $F$; nuclear biprojective K"{o}the algebras $\lambda (P)$ which are Fr'echet spaces or $DF$-spaces; the algebra of distributions ${\mathcal{E}}^{\ast }(G)$ on a compact Lie group $G$.