Home office use deduction

[curiousgeorge]

My friend, Jane, was recently hired for a work-at-home job. She lives alone in a condo jointly owned by her and her mother. Her mother pays monthly condo fees, mortgage, and real estate tax.
Does Jane have to pay all of these in order to take a home office (HO) deduction on her tax return? Or can she pay half? If so, how would the HO be calculated?
Thank you! 

[taxref]

Assuming she meets the "convenience of the employer" and the "regular and exclusive use" tests, a home office deduction is computed using Form 8229.  The form allocates her home expenses to the percentage of business space in her home.  Any amounts she pays to her mother would be her home expenses.  

Since she is an employee, the bottom line deduction from Form 8229 is a miscellaneous itemized deduction.  She can only take the deduction if she itemizes, and only to the extent that all of her miscellaneous itemized deductions exceed 2% of her AGI.

[TheOtherMe]

Some work at home jobs are 1099 jobs.  I've looked in to some and that was what they were.  If that is the case, it would go on Schedule C and no 2% haircut.