So I gather we define a Goodstein relation G such that [xGy] in PA if [y = Goodstein(x)] in ZFC, then you're saying PA plus the axiom [not(exists y, (256Gy and exists z, (yGz)))] is inconsistent but the proof of that is huge because it the proof basically has to write an execution trace of Goodstein(Goodstein(256)). That's interesting!
So I gather we define a Goodstein relation G such that [xGy] in PA if [y = Goodstein(x)] in ZFC, then you're saying PA plus the axiom [not(exists y, (256Gy and exists z, (yGz)))] is inconsistent but the proof of that is huge because it the proof basically has to write an execution trace of Goodstein(Goodstein(256)). That's interesting!