Hi all,

first some definition of notation (as introduced here:here)

{i} supported state i (chain of valid transitions & signatures present)

{i}* supported state on-chain

{i}-> (i+1)_A participant A made his move (from i to i+1 and signed it)

Now suppose we have a 3 participant channel with participants A,B,C in on-chain state i, A made his next move from the off-chain supported state {j}:

{i}* ->{j} -> (j+1)_A

and B does not make his move (might be temporarily offline).

In the docu I read that forceMove challenging is only possible based on supported states (which in my opinion would be {j} but not (J+1)_A.

Is this understanding correct?

This would mean A could only challenge {j} (allowing then in the pessimistic path do defund based on the latest supported state which is OK and secure).

So we have

{i}* ->{j}* ->challenge and (j+1)_A of-chain known

however this would not allow for B coming online and responding such that:

{i}* ->{j}* -> (j+1)_A ->(j+2)_B

right?

Or could we challenge as follows (showstopper: j+1 is not a supported state, might have outcome changes B and C do not agree upon):

{i}* ->{j}* -> (j+1)_A *

such that B responding gives

{i}* ->{j}* -> (j+1)_A * -> (j+2)_B*

Therefore, the only solution is A or C challenging {j}

{i}* ->{j}* ->challenge and (j+1)_A of-chain known

now B could of-chain provide his ->(j+2)_B, and C his ->(j+3)_C on top, such that anybody could

checkpoint the resulting supported state {l} (j+1)_A

{i}* ->{j}* ->challenge-> checkpoint {l}*, with transition to {l}=(j+1)_A -> (j+2)_B -> (j+3)_C

However, in the respond docu, I read that the mover can respond with his move;

B in fact is the off-chain mover, but not the mover to the ‘challengeable’ state {j} (namely required to be a supported state).

A on the other hand could challenge {j} and repsond with his ->(j+1)_A move, which however leaves the channel in open, but not in challenge mode.

You see, I’m confused once again…

Alex