Effective mass (solid-state physics) from both sides gives where is the th element of , is the th element of , and are the th and th elements of , respectively, and is the total energy of the particle according to the Planck–Einstein relation. The index is contracted by the use of Einstein notation (there is an implicit summation over ). Since Newton's second law uses the inertial mass (not the gravitational mass), we can identify the inverse of this mass in the equation above as the tensor This tensor expresses the change in group velocity due to a change in crystal momentum. Its
Mercy Multiplied three financial principles for the program: According to the three guiding principles that founder Nancy Alcorn established, the Mercy Multiplied website states that they do not accept government funding, and as such, are supported solely by donations from individuals, organizations and other ministries. With regard to fund raising events, Mercy Multiplied host gala dinners, Christmas donation drives and running marathons throughout the year, and invite visitors to their website to donate by becoming a financial partner or "sponsoring" a girl. Mercy Multiplied also sell resources to raise funds such as books and sermons by founder Nancy Alcorn, as well as