Question

What is time symmetry

Answer 1

-symmetry or time reversal symmetryis the theoretical symmetry of physical laws under the transformation of timereversal: ...

Hence 

time is said to be non-symmetric, or asymmetric,

except for equilibrium states when the second law of thermodynamics predicts thetime symmetry to hold

Answer 2

T-symmetry or time reversal symmetry is the theoretical symmetry of physical laws under the transformation of time reversal:despite the fact that in constrained contexts one may in finding this symmetry, the observable universe itself does not show symmetry underneath time reversal, especially because of the second legislation of thermodynamics. Hence time is said to be non-symmetric, or uneven, except for equilibrium states when the second law of thermodynamics predicts the time symmetry to hold. Nonetheless, quantum noninvasive measurements are envisioned to violate time symmetry even in equilibrium,[1] contrary to their classical counterparts, even though it has not but been experimentally validated.

Time asymmetries are mostly exceptional as among these intrinsic to the dynamic physical laws, these because of the preliminary stipulations of our universe, and due to measurements.

*The T-asymmetry of the vulnerable drive is of the first type,
*The T-asymmetry of the 2nd regulation of thermodynamics is of the second kind, whilst
*The T-asymmetry of the noninvasive measurements is of the third variety.

hope it helped u