A little explanation might be needed. I mean mutual credit the way that it's defined here:a type of alternative currency in which the currency used in a transaction can be created at the time of the transactionImagine you have a network of accounts. Each starts out at zero and any account can extend a limited line of credit to any other account. My total balance would just be the sum of what others owe to me, minus the sum of what I owe to others. Lines of credit can be represented with a simple table. In pseudo-code for some kind of ORM:type LineOfCredit struct {    IOURecipient  string, // Account ID of IOU recipient    IOUIssuer     string, // Account ID of IOU issuer    Owed          int,    // Amount owed to IOU recipient    Limit         int,    // Maximum IOU amount}To hopefully make the concept clearer: The recipient would generally be the person getting paid in a transaction; the issuer is the person paying. For example:Persons A requests service from person BB agrees and extends a line of credit to A A issues IOU to BThese debts may or may not be settled in some real-world currency, at some point, but the idea is that they eventually cancel out one another, either directly or indirectly.I'll use $ to represent the currency, though, of course, the units are arbitrary. Imagine that...Bob owes $20 to SallySally owes $20 to JoeJoe owes $20 to BobIt's clear that there's no actual debt here and they don't owe one another anything. So, how would you detect these kinds of cycles in a balance sheet and then eliminate them? Is this a problem for graph theory? I imagine this can be represented as a directed network graph. My knowledge here is very limited, but I understand it's possible to detect cycles with Tarjan's strongly connected components algorithm, though that doesn't seem to offer much help, especially as those cycles get larger. I also thought that, maybe, shortest-paths could be crunched at the time of a transaction, with the reciprocals of outstanding debts represented as edge-weights/distances.I think Ripple pay possibly did something like this, but I'm having trouble finding a precedent. 
In a mutual credit network, how would you program an automatic jubilee?
algorithms;graph traversal