4+1-dimensional space-time
You know something impressive is happening when ‘4+1’ doesn’t equal ‘5’.
It’s common shorthand for 4 spatial dimensions, and 1 time-dimension, stressing that there is indeed a split, and that not all dimensions are equivalent. Perhaps, given the compactification of 1, it should be 3+1+1, but I’ve never seen that used.
Thanks, I wasn’t sure whether the +1 was the time or the compact dimension.
Generally, it means that one of the signs is reversed in the ‘inner product’.
You know something impressive is happening when ‘4+1’ doesn’t equal ‘5’.
It’s common shorthand for 4 spatial dimensions, and 1 time-dimension, stressing that there is indeed a split, and that not all dimensions are equivalent. Perhaps, given the compactification of 1, it should be 3+1+1, but I’ve never seen that used.
Thanks, I wasn’t sure whether the +1 was the time or the compact dimension.
Generally, it means that one of the signs is reversed in the ‘inner product’.