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zabop
  • Member for 3 years, 8 months
  • Last seen this week
  • Oslo, Norway
27 votes
2 answers
562 views

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

11 votes
1 answer
508 views

How to solve equation of motion of cosmological scalar field

4 votes
1 answer
244 views

Solving heat equation using Fourier-series with non-homogeneous assymetric bondary conditions

4 votes
1 answer
85 views

Why is $\delta^b_e\nabla_c {R_{cad}}^e$ equal to $\nabla^b {R_{cadb}}$ - ie how to contract the Bianchi identity properly

3 votes
2 answers
484 views

Proof that each element of finite arbitrary group belongs to unique conjugacy class - question on step which takes inverse of a product

3 votes
2 answers
487 views

Why do all elements commute in centre of an arbitrary finite group?

3 votes
1 answer
80 views

Why is the definition of sin and cos in terms of exponentials is similar to the definition of $L_x$ & $L_y$ in terms of raising & lowering operators?

3 votes
0 answers
60 views

How to estimate parameter functions of Sturm-Liouville operators using functional gradient descent?

3 votes
1 answer
370 views

Solving the heat equation in spherical polars with nonhomogeneous boundary conditions

2 votes
2 answers
94 views

Is Mercator projection an affine trasformation?

2 votes
0 answers
222 views

Shortcut to find imaginary part of analytic function given real part, without standard form of Cauchy-Riemann equations?

2 votes
1 answer
230 views

How to 2D Fourier Transform a chequerboard-like function by hand?

2 votes
1 answer
31 views

Poisson's equation-like formula in axis-symmetric Galactic potential in terms of Oort constants

2 votes
1 answer
49 views

Deriving the first moment of Collisionless Boltzmann Equation in Spherical Polar Coordinates

2 votes
1 answer
201 views

Calculation of Christoffel symbols of Schwarzschild metric using Lagrangian

2 votes
0 answers
51 views

How many independent connection coefficients are there for a given dimensional metric?

2 votes
2 answers
118 views

Is it special for a Lagrangian to equal its first integral?

1 vote
1 answer
424 views

How to take algebraic Bianchi identity into account when calculating the number of independent components of Riemann curvature tensor

1 vote
0 answers
25 views

Parametrized solution for motion of radially infalling object

1 vote
0 answers
20 views

How to find curve which I have the tangent vector field to in polar coordinates?

1 vote
0 answers
38 views

How to find the right combination of general solutions to fulfill nonhomogeneous boundary conditions when solving heat equation in spherical polars

1 vote
1 answer
358 views

How to interpret invariant subspaces in the definition of irreducible representation?

1 vote
0 answers
149 views

How to show that the gradient of a vector field is an order 2 tensor - and what can we learn from doing it wrong?

1 vote
2 answers
141 views

How can $(A \times \nabla) \times B$ be rearranged?

1 vote
1 answer
45 views

Do the free indices referring to the same dimension have to be denoted by the same letter on both sides of an expression when using Einstein notation?

1 vote
1 answer
227 views

Proof that $H \cap K$ is a group if $H$ and $K$ are subgroups of $G$ [duplicate]

1 vote
1 answer
45 views

Clarification of definition of quotient group - Does $Na, a \in G$ mean "cosets of $N$ in $G$"?

1 vote
1 answer
84 views

What property does the function hold which values equal the complex conjugate of the function with argument with opposite sign?$X(-\nu)=X^*(\nu)?$

1 vote
2 answers
198 views

Is there any matrix $A$ for which $A^{\dagger}A=AA^{\dagger}$ but $A\neq A^{\dagger}$?

1 vote
5 answers
47 views

How do I get the equality $\sum_{l-s}^{l+s}(2j+1) = (2l+1)(2s+1)?$