Invincible (Skillet album) Invincible (Skillet album) Invincible is the third studio album by American Christian rock band Skillet. It was released in 2000 from ForeFront Records and Ardent Records. This album continues the electronic rock that was heard on their previous release but marks the exit of original guitarist, Ken Steorts, and the entrance of his replacement, Kevin Haaland on guitar, as well as John Cooper's wife Korey on keyboards, loops, sampling and programming. All songs written by John L. Cooper, except where noted. There was a music video made for the song "Best Kept Secret". It was the first video by the
Envy-free item assignment the agents' utilities are not additive, the MNW solution is not necessarily EF1; but if the agents' utilities are at least submodular, the MNW solution satisfies a weaker property called "Marginal-Envy-Freeness except-1-item" (MEF1). There is an alternative criterion called Envy-freeness-except-cheapest (EFx): For each two agents A and B, if we remove from the bundle of B "any" item, then A does not envy B. EFx is strictly stronger than EF1. As of this writing, it is not known whether EFx allocations always exist. Given an allocation "X", define the envy ratio of "i" in "j" as: so the ratio is