如何理解keras点层

Question

以下代码来自互联网

       # Both inputs are 1-dimensional
       book = Input(name = 'book', shape = [1])
       link = Input(name = 'link', shape = [1])

       # Embedding the book (shape will be (None, 1, 50))
       book_embedding = Embedding(name = 'book_embedding',
                                  input_dim = len(book_index),
                                  output_dim = embedding_size)(book)

       # Embedding the link (shape will be (None, 1, 50))
       link_embedding = Embedding(name = 'link_embedding',
                                  input_dim = len(link_index),
                                  output_dim = embedding_size)(link)

       # Merge the layers with a dot product along the second axis (shape will be (None, 1, 1))
       merged = Dot(name = 'dot_product', normalize = True, axes = 2)([book_embedding, link_embedding])

我是Dot层的新手，我的问题是：

1. 能给我一个例子，说明如何使用点层从书本矢量和链接矢量中获取新矢量

2. 归一化=真，轴= 2表示什么？