4.6 All Symbols
We will now discuss about a predicate proposition. Let us demonstrate for x holds p[x] & q[x]. Further, p[x] means a predicate that includes x and it does not mean that brackets are permitted.
for x holds P[x] & Q[x]
thus Q[x]; (thesis)
The word let exists as an opposite of for from all symbols. P is demonstrated by thus P[x] with leaving let x as it is. Further, we will demonstrate Q with Q[x].
If it does not get confused, this letter can be changed. For example, the letter can be changed to y.