System to track verious small debts between friends and generate a minimal set of payments to bring all parties back to owing nothing to anyone else - back to a tabula rasa.
Accountspecifies an entity which can be credited or debited amounts.
Transactiondefines a credit to one account matched by one or more debits to other accounts.
Ledgeris a series of transactions which can calculate balances
Balanceis the entire collection of transactions in a ledger which include a specific account.