Proper accelerationIn relativity theory, proper acceleration is the physical acceleration (i.e., measurable acceleration as by an accelerometer) experienced by an object. It is thus acceleration relative to a free-fall, or inertial, observer who is momentarily at rest relative to the object being measured. Gravitation therefore does not cause proper acceleration, because the same gravity acts equally on the inertial observer. As a consequence, all inertial observers always have a proper acceleration of zero.
Bootstrapable buildsBootstrapable builds, a process of compiling software that doesn't depend on (compiler) binaries that aren't build from source by this process. This process can protect against compiler backdoors: if the build process doesn't depend on binary code that is difficult to audit, then a compiler backdoor cannot be hidden in compiler binaries anymore. A way to tackle the issue for a Software distributions is to reduce the size of the binaries used to bootstrap the distribution until there are not needed anymore or that the size is small enough to be easily reviewed by humans.
Position (geometry)In geometry, a position or position vector, also known as location vector or radius vector, is a Euclidean vector that represents the position of a point P in space in relation to an arbitrary reference origin O. Usually denoted x, r, or s, it corresponds to the straight line segment from O to P. In other words, it is the displacement or translation that maps the origin to P: The term position vector is used mostly in the fields of differential geometry, mechanics and occasionally vector calculus.
