# Arbitrage and state price formulation

I must be missing something really obvious due to my temporary obtuseness. Can someone please help me see the obvious? :-P Thank you.

I am just browsing Darrell Duffie's Dynamic Asset Pricing Theory. Can someone help me formulate the multiperiod arbitrage trading strategy $\theta_t$ mentioned in Section 2C in terms of the arbitrage $\theta$ in Section 1A, which is asserted by the sentence "The reader should become convinced that this is the same notion of arbitrage defined in Chapter 1."? My confusion lays in the fact that $\theta_{t-1}$ and $\theta_t$ are now two portfolios than one as in Chapter 1A. How does one reconcile the difference?

The relevant excerpts of Section 1A, 2B and 2C are as below.