differenceexistentialsnegation
Yesterday I got a message that
"There will be no introduction lecture"
Now, I'm not sure if it's a mistake or it's another grammatical way to say
"There will not be a lecture".
If they are both valid, is there a difference between them? (such as register, etc.)
Grammatical mistake and grammatical error have no semantic difference. They are used interchangeably. Between the two, grammatical error is much more common. Here's a Google Ngram chart that shows their popularity.
Note that grammar error and grammar mistake are also used, but are less common than their respective adjectival versions. See below:
A "dichotomy" splits a category into two subcategories. A "false dichotomy" is a logical error that incorrectly asserts that something must be in one category or the other; it claims the thing cannot be both or partway in between.
A "duality" describes two aspects of a single thing. For example, applying the "wave-particle duality" principle to light says that for some purposes, a small enough amount of light behaves like a particle; and for other purposes, it behaves like a wave.
Best Answer
It is not a mistake.
As you wrote, it has the meaning of "There will not be an introduction lecture".