Performs a permutation-based significance test for the O-information of a candidate variable subset.
Details
This procedure corresponds to the first stage of the hypergraph construction framework proposed by Possenti et al. (2026).
The null hypothesis assumes mutual independence of the variables. A null distribution is generated by independently permuting each variable, thereby preserving univariate distributions while destroying multivariate dependence structure.
The Monte Carlo p-value is computed as:
$$ p = \frac{ \#(|\Omega_{perm}| \ge |\Omega_{obs}|) + 1 }{ N_{perm} + 1 } $$
where \(\Omega_{obs}\) is the observed O-information and \(\Omega_{perm}\) are values obtained from permuted datasets. The smallest possible p-value is \(1/(N_{perm}+1)\).