[求助]读《Anvanced linear algebra》时关于两个定义的疑问

xiejianqiao

下面这两个定义有什么区别吗？
The maximum（largest top ） element of P, should it exist, is an element M∈P
with the property that all elements of are less than or equal to
that is, p∈P→p≤M
The maxmalelement of P is an element M∈P with the property that there is no larger element in P
that is, p∈P，m≤p→p＝M