= Minimal model of a wedge of simply connected spheres
For a finite <wedge sum> of spheres of dimensions $n_i\ge2$, let $L=\mathbb L(e_i)$ with $|e_i|=n_i-1$ and zero differential. Its <Chevalley–Eilenberg cochains of a graded Lie algebra> are a minimal commutative <differential graded algebra>: one generator dual to each Lie <basis> word has degree one more than that word, and its differential is dual to the Lie bracket. Its <cohomology> is $\mathbb Q\oplus\bigoplus_i\mathbb Q a_{n_i}$ with all positive products zero. One way to compute this is $U(L)=T(e_i)$; the augmentation module has a length-one free resolution, so the corresponding Ext has only the unit and the dual generating classes.
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