You mean statement (1) ?

All algorithms must start somewhere, you just pick (Inf,-Inf) for the first pair in algorithm A.¹ And since you already know the result, it's a pseudo comparison - you skip the step it in the constructed algorithm A'.

Just imagine playing the game with C' 100 covered cards plus two extra dummy cards in your head and applying an algorithm A for C 102 cards.

The dealer doesn't know what's in your head, he'll never hear a question about the dummy cards, because you already know the necessary results to continue your algorithm.

Two things are relevant:

• you got the min&max of C' in the end
• you asked the dealer 3 questions less than you would have needed for 102 covered cards.

¹) it doesn't matter if it was unlikely. What matters is that A is guaranteed to work with any starting pair.