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Qmechanic's user avatar
Qmechanic
  • Member for 13 years
  • Last seen this week
44 votes
Accepted

Why is this translation not a linear transformation?

23 votes

Relation between $SU(4)$ and $SO(6)$

22 votes

Why is the product of two rotation matrices not commutative?

19 votes

Equivalence of Two Lorentz Groups $O(3,1)$ and $O(1,3)$

14 votes

Dirac delta function of non-linear multivariable arguments

12 votes

If $XYZ=ZXY$ does $e^Xe^Ye^Z=e^Ze^Xe^Y$?

11 votes

Is the exponential map to the indefinite special orthogonal groups $SO^+(p,q)$ surjective?

11 votes
Accepted

An outrageous way to derive a Laurent series: why does this work?

9 votes

Area integral over complex plane of non-holomorphic gaussian $e^{-z\bar{z}}$

9 votes
Accepted

When can the Lagrangian be squared without changing the stationary path?

8 votes

I have heard that $SO(3)$ is "isomorphic" to a sphere. Is this true? if so, how do we prove it?

8 votes

Why is $\frac{\operatorname dy'}{\operatorname dy}$ zero, since $y'$ depends on $y$?

8 votes

Fourier-like expansion of a closed curve in 2D

8 votes

Why can't rotations be represented by purely imaginary quaternions?

7 votes
Accepted

Functional derivatives in (Physics) Field Theory

7 votes

Existence of the Pfaffian?

6 votes

Dirac delta function $\delta(f(x))$ of function $f$ with a higher-order zero

6 votes
Accepted

Functional Equation $f(x+y)-f(x-y)=2f'(x)f'(y)$

6 votes

Why are the fundamental and anti-fundamental representation in $\text{SL}(2,\mathbb{C})$ not equivalent?

6 votes

Minimizing a functional with a free boundary condition

6 votes

Unitary invariance

6 votes

Why is this a first integral? - particle near Schwarzschild black hole

5 votes

Euler-Lagrange-type equation for a more natural variational problem

5 votes
Accepted

Limitation of Lagrange Multipliers

5 votes
Accepted

Is a stationary point for length functional automatically a local minimum?

5 votes
Accepted

Exact solution to Dirac delta perturbation for particle in a box

5 votes

Non-symmetric matrix with orthogonal eigenvectors

5 votes
Accepted

Same number of independent parameters for $SO(n)$ and $O(n)$

5 votes

What is an example of function $f: \Bbb{N} \to \Bbb{Z}$ that is a bijection?

5 votes

Show the Lagrange equations can also be written on Nielsen's form

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