I currently have the elemental resists formula set to:
CODE
(1 - (1 - SIGMA(aura_bonus*aura_rank)) * PI(1 - eq_bonus)) * (1 + (ability_bonus*ability_rank))
I could not actually find a formula on the wiki, so I did the above based on the assumption that those abilities modify the resistances separately from the eq and combined aura bonus, in the same way that burden and interference affect evade and critical chances.
Based on your feedback, I'm assuming the elemental resist abilities should actually be applied as follows:
CODE
(1 - (1 - SIGMA(aura_bonus*aura_rank)) * PI(1 - eq_bonus) * (1 - (ability_bonus*ability_rank)))
As long as you are reading this thread, I'd like to confirm that the capacitor and juggernaut bonuses are applied separately from (i.e. multiplicatively with) the HP and MP tank bonuses.