Lower bound for quasirandom-forcing linear combinations

A linear combination of permutation patterns is quasirandom-forcing if it has the quasirandomness-forcing property studied in the paper. The number of terms means the number of permutation patterns appearing in the linear combination, and coefficients may be positive or negative. Lower-bound conjecture. There are no quasirandom-forcing linear combinations with fewer than six terms, even if negative coefficients are allowed. The paper proves the corresponding result for positive coefficients, while the extension to arbitrary coefficients remains open because vanishing covers and possible infinite families must be analyzed.