A: They have different meanings both literally and practically.
"Power of attorney" refers to this kind of work which is charged, entrusted, required to be written and has specified contents.
For example, Zhang San is a calligrapher, and Li Si entrusts him to write a picture of Virtue Carrying Things. Zhang San will withdraw money: Li Si's power of attorney.
The actual effect is to tell others that this painting was written by Li Si and Zhang San. The principal and the principal may or may not know each other.
As shown above, this couplet written by Li Hongzhang: the water flows smoothly, the wind is clear and the moon is bright, which is a superior Zen meaning. The title of the previous paragraph: "The book was written by Jichuan's eldest nephew", which means that Jichuan's nephew asked him to write it. Of course, this is mutual understanding.
Let's take a look at Mr. Sha Menghai's couplets as follows: Qian Fan passed by the sunken ship and Wan Muchun was in front of the sick tree. The title of the previous paragraph: "Mr. XX asked Liu Mengde to write a sentence" means that they may know what Mr. XX asked him to write.
The meaning of "Yazheng" is similar to that of "upright axe", "upright wrist" and "benefiting truth". They all ask others to give their works some suggestions to improve themselves. In fact, they are all modest words.
Both the giver and the receiver know each other. Generally, the works written by junior, students and subordinates show respect to elders, teachers and superiors, hoping to get some advice.
As shown above, this calligraphy work by Mr. Xu Beihong: mourning and thinking about war, stands upright in the sky. The inscription reads: "Mr. Deshen is beneficial to Zheng", which means to give this work to Mr. Deshen for his advice.
Let's take a look at Mr. Zhang Daqian's calligraphy work: Drunk oranges sing maple. The inscription reads: "Brother Sheng Zhai is right", which means to give this work to Brother Sheng Zhai for his advice.
This is the difference between "entrusted books" and "elegant".