NOT KNOWN DETAILS ABOUT PNL

$ From the "function case" you liquidate the portfolio at $t_1$ realising its PnL (let me simplify the notation a little)$begingroup$ The pnl calculation is finished in 2 techniques. By definition, you value your portfolio as of now, you worth your portfolio as of yesterday, and the primary difference is going to be your pnl.Now, in the above ratio