Note that RB are not fungible. They're always issued from one person to another.
For simplicity, I was assuming that there is only one RB issuer. However, I agree that this is not a necessary requirement. Just like in Northern Ireland, Scotland or Hong Kong there are multiple bank note issuers, there could be also multiple RB issuers. To what extent they would be treated as fungible is of course another question.
Anyway, you're considering ripple a money substitute in the austrian sense, so maybe we should take it out of our example.
I do not have a theoretical objection to any debt instrument becoming a money substitute. The question is the likelihood. It needs to offer something as a method of payment which the money-proper does not. With gold/fiat, this is straightforward. With Bitcoin, not so much. Even the hypothesised advantages of ripple might not be sufficient to cause enough demand, I just think it makes more sense than with classical demand deposits.
Let's just use regular credit transactions. I meant money substitutes as just other medium of exchange different from money, don't know if this fits with the austrian definition.
In Austrian terminology, as far as I know, money-substitute is a debt claim on money-proper which is generally accepted as a medium of exchange instead of money.
I've heard about Gesell, I read Alternatives to Legal Tender (or something like that) by Thomas Greco. I agree with the quote, however it neglects the informational function of money, i.e. the intertemporal and interpersonal coordination of plans, as well as the speculation (uncertain future). These needs might affect the outcome.
When I said inflation I meant price inflation rather than monetary inflation (what you defined as inflation). I don't care if credit it's going to be considered part of M or not. What I want to know is if prices would rise.
This is a slightly controversial topic in the Austrian circles. The main problem, as far as I understand it, is not really whether prices would rise (they might not, assuming the extra supply is offset by extra growth of the economy), but that the new money is "injected" into the economy without causing corresponding production costs. This causes a redistribution of purchasing power as the new money propagates through the economy, and leads to boom & bust cycles (Austrian Business Cycle Theory).
I'm interested in both the Austrian and the Keynesian view on this.
I am not an expert in the Keynesian school, but I think Keynes argued that if there is involuntary unemployment, expansion of money supply does not cause inflation.
If we had only one country with one currency (say gold) and 100% reserve for banks by law, will private credit between partners push price inflation?
Under typical circumstances, no. This is actually how the full reservist branch of the Austrian school sees a proper economy.