User:Limeheadnyc/Sandbox

Testing some math symbols:

$$ S = \int d^3 x \, \phi(x) (-\partial^2 + m^2)\phi(x). \, $$

$$ S = - \left [ \sum_{x,\hat{\mu}} \phi(x) ( \phi( x + \hat{\mu} )+\phi(x-\hat{\mu})) \right ] + (6 + m^2) \sum_{x} \phi^2(x) $$

$$ G(x,y,z) \equiv \langle \phi(x,y,z)\phi(0,0,0) \rangle $$

$$ \tilde{G}(z) = \sum_{x,y} G(x,y,z) $$

$$ G(\mathbf{x}) = \int \frac{d^3 p}{(2 \pi)^3} \frac{e^{-i \mathbf{p} \cdot \mathbf{x}}}{\mathbf{p}^2 + m^2} $$