Equation 59 · Part 1 · The Atlas That Refuses to Close
Symbol X^mu
What this part means
u is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Its job in the formula
u is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Full expression→Symbol X^mu→Article meaning
The passage around this formula
The first, the covariant centre of energy, transforms simply as the spatial part of a four-vector under a change of Lorentz frame — exactly the property was built with above — but its three spatial components fail to commute with each other once spin is present, by an amount proportional to the spin itself. The second, constructed by Newton and Wigner for exactly this purpose and reproduced in Pryce’s classification as a distinct…
Learn the underlying idea
An exponent tells how a base is used in multiplication. In x³, x is the base and 3 is the exponent: x³ = x × x × x.
Open the illustrated exponents: repeated multiplication and powers guide →
See this notation across published equations →
Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.