A strategy S1 is said to strictly d

A strategy S1 is said to strictly dominate another strategy S2 if, given any
collection of strategies that could be played by the other players, playing S1
results in a strictly higher payoff for that player than does playing S2. Thus we
can say that if player A has a strictly dominant strategy in a situation, it will
always give at least as high a payoff as any other strategy, whatever player B
does. A rational player will always adopt a dominant strategy if one is available.
Therefore, in any static game involving discrete strategies, we should always
start by looking for a dominant strategy