let $(\Lambda V,d)=(\Lambda (a_1,...a_n),d)$ be a graded commutative differential algebra, and $(\tau;a_1,...a_n)$ be a connected, finite c-finite tower with odd spectral sequence $(E_i,d_i)$. Assume $deg~a_i$ is odd for all $i$. So $(\Lambda V,d)$=Exterior algebra. We have $\Lambda (a_1,...a_n)=\Lambda a_1\otimes\Lambda (a_2,...a_n)$. The resulting spectral sequence $E_i$ satisfies (of course, $deg~a_1>1)$, $E_2^{p,q}=(\Lambda a_1)^p\otimes H^q(\Lambda (a_2,...a_n),d_\overline{\tau}).$ The sequence collapses at the nth term where $n=deg~a_1+1.$ My question is under what conditions the spectral sequence collapse at the 2nd term?
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