[Grammar] comparative structure

[hotapplepie]

Hi,
I want to ask about some structure problem in comparative.
My grammar book has mentioned a structure like "The boy is as smart as John,"
and which is what I have seen the most common types of comparative structure.
So when I saw another type of structure like"A man as rude as him could offend a lot of people,"
I am wondering if it's a correct or formal usage.
My concern is the part of "A man as rude as," which donsn't have any verb in.
Is it a short form of "A man who is as rude as," or it's just that "as" is a preposition placed after noun.
But as I know,the first "as" is an adverb representing the meaning of "the same" to modify adjective.
I am confused now in this grammar. Would you explain it's structure to me please?
And i am thinking if this is a correct grammer,
then how about cases like "A man smarter than John doesn't exist."
Is this also a correct usage?
I can't find these types of usage in my grammar books.

Thanks!

 

[Raymott]

Yes, it means "A man who is as rude as him ..."

 

[hotapplepie]

Yes, it means "A man who is as rude as him ..."

Thank to your reply,
but excuse my poor English,
I still don't know if "A man smarter than John doesn't exist." is also correct.
is it means "A man who is smarter than John doesn't exist."?
is this the same usage as ""A man who is as rude as him ..." ?

 

[Raymott]

Thank to your reply,
but excuse my poor English,
I still don't know if "A man smarter than John doesn't exist." is also correct.
Does it mean "A man who is smarter than John doesn't exist."?
is this the same usage as ""A man who is as rude as him ..." ?

Yes it's correct and it means the same thing.