1. (a) That's right. A, the principal in this case, has appointed B as her agent, and expressly authorised him to bid up to $50,000 to purchase a particular painting. This expressly given authority vests B with the power to represent A in bidding for that painting, and to buy it for her if possible.

We refer to the agent's authority as 'express' when it is explicitly set out or stated by the principal, either orally or in writing.