Ambient pressure concept of pressure becomes irrelevant, and it is undefined at a gravitational singularity. The SI unit of pressure is the pascal (Pa), which is a very small unit relative to atmospheric pressure on Earth, so kilopascals (kPa) are more commonly used in this context. The ambient atmospheric pressure at sea level is not constant: it varies with the weather, but averages around 100 kPa. In fields such as meteorology and underwater diving, it is common to see ambient pressure expressed in bar or millibar. One bar is 100 kPa or approximately ambient pressure at sea level. Ambient pressure may in
Pascal matrix both "L" and "U". In other words, matrices "S", "L", and "U" are unimodular, with "L" and "U" having trace "n". The elements of the symmetric Pascal matrix are the binomial coefficients, i.e. In other words, Thus the trace of "S" is given by with the first few terms given by the sequence 1, 3, 9, 29, 99, 351, 1275, … . The Pascal matrix can actually be constructed by taking the matrix exponential of a special subdiagonal or superdiagonal matrix. The example below constructs a 7-by-7 Pascal matrix, but the method works for any desired "n"×"n" Pascal matrices. (Note