Mudrex connects with multiple open book exchanges i.e. when a strategy places an order to buy/sell a particular asset at the quoted price, Mudrex places an order on the chosen exchange which then tries to find the corresponding sell/buy order for the same.
On the exchanges, there might be multiple users placing multiple orders at the same time and price
Let's consider an example where a User A has placed an order to buy 100 Ripple at a price of 50 each. On the sell side, there is a user B who is willing to sell 20 Ripple at 50 each. In this case, the Mudrex matching engine will match the orders placed by Users A and B. User B's order will be completely filled while the order placed by User A will be partially filled.
Post this, the order placed by User A will continue to exist except that the quantity required to be filled now is just 80 Ripple tokens. The above is known as partial execution.