Final answer:
Let expressions and function application are not semantically equivalent. Let expressions bind variables to values, while function application executes a function with certain arguments.
Step-by-step explanation:
Regarding whether let expressions and function application are semantically equivalent, the answer is False. In programming, particularly in functional languages, a let expression is used to bind variables to values. The scope of these variables is usually the block of code in which they are defined. On the other hand, function application involves executing a function with certain arguments and may not necessarily involve the creation of new variable bindings. While both can be used within computations and may sometimes seem interchangeable, they serve different semantic purposes.
To illustrate, consider the let expression let x = 10 in x + 1, which binds the value 10 to the variable x and then calculates x + 1. In contrast, a function application applies arguments to a function, like in add(10, 1), where add is a function that sums its arguments.