Let consist of finite normalized sequences for which every scalar combination and sign change satisfy . These inequalities give a closed tree on a Polish space when is separable. An infinite branch is an unconditional basic sequence. If there is no such sequence, each fixed-constant tree is well-founded and has countable rank of a well-founded tree. Consequently, finite unconditional configurations with one fixed constant and arbitrarily high countable ranks force an infinite unconditional sequence.

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