What are i.r.c section 179; i.r.c.section 457A deferred compensation; i.r.c section 168(K) bonus depreciation for?

Hello,

I am helping my daughter working on her CT tax file.

Under CT state tax section,  income, here is income that CT handles differently, miscellaneous, there are 

i.r.c section 179;

i.r.c.section 457A deferred compensation;

i.r.c section 168(K) bonus depreciation

I do not understand what are these for? Then I did some research online and find out:

i.r.c section 179;                                                      is for business

i.r.c.section 457A deferred compensation;       is for employee who work for a tax-exempt organization 

i.r.c section 168(K) bonus depreciation              is for business.

My daughter only get W2 from a normal company, so I think all these are not her case.

I am not tax person, I am not sure whether my understanding is correct.

Please help me know 

Thanks