`log_a x < log_b x` is the mathematically correct result. Due to inherent rounding from floats being a finite representation of real numbers, `log_a x <= log_b

`log_a x < log_b x` is the mathematically correct result. Due to inherent rounding from floats being a finite representation of real numbers, `log_a x <= log_b x` would be expected from any correct implementation using floats. So either `true true false` or `true false true` would be reasonable. (I made a mistake in the previous comment, LuaJIT returns `<` for me, just like in your comment, not `=`.) The topic of the post is that in PHP and Lua (without LuaJIT), sometimes this inequality doesn't hold, and instead we get `log_a x > log_b x`, which is very incorrect and cannot be explained away by rounding. Does that make more sense?