The key question is when has the business activity started.  There can be expenses which are considered as "start-up" costs and these maybe either expenses or amortized depending on the nature of the expenses.

Normally, the start date for a business is when the business is registered. This means that a company like an LLC or a partnership is responsible for paying taxes on the date they register with a particular state. It also may be possible for a business to choose their start date.

Business start-up usually can be claimed in the year the business was started.  One also can amortize these costs over a certain number of years.

It is unclear why you state that the initial cost of the Seminar is not a business start-up cost.

Also, expenses of this type could be deducted as "Other Expenses".