Physlib.SpaceAndTime.Space.LengthUnit
Units on Length
A unit of length corresponds to a choice of translationally-invariant metric on the space manifold (to be defined). Such a choice is (non-canonically) equivalent to a choice of positive real number. We define the type `LengthUnit` to be equivalent to the positive reals.
On `LengthUnit` there is an instance of division giving a real number, corresponding to the ratio of the two scales of length unit.
To define specific length units, we first state the existence of a a given length unit, and then construct all other length units from it. We choose to state the existence of the length unit of meters, and construct all other length units from that.
Division of LengthUnit
The scaling of a length unit
Specific choices of Length units
To define a specific length units. We first define the notion of a meter to correspond to the length unit with underlying value equal to `1`. This is really down to a choice in the isomorphism between the set of metrics on the space manifold and the positive reals. From this choice of meters, we can define other length units by scaling meters.
Relations between length units
37 declarations
The numerical value of a length unit is non-zero ()
For any length unit , its underlying numerical value is not equal to .
The numerical value of a length unit is positive ()
For any length unit , its underlying numerical value is strictly positive, satisfying .
Default is
The type , representing the set of physical length units (isomorphic to the positive real numbers ), is inhabited. A default instance is provided, which is defined as the length unit with the underlying value .
Division of length units as
The division operation for two length units is defined as the ratio of their underlying values , yielding a non-negative real number in .
for Length Units
For any length units with underlying numerical values and , the division is equal to the quotient of their values regarded as a non-negative real number in .
for length units
For any length units , the ratio is not equal to in the non-negative real numbers .
for length units
For any length units , the ratio is strictly greater than in the non-negative real numbers .
for length units
For any length unit , the ratio of to itself, denoted by , is equal to in the non-negative real numbers .
for length units
For any length units , the ratio of to is equal to the reciprocal of the ratio of to . Mathematically, this is expressed as: where the division denotes the ratio of the underlying numerical values of the length units, resulting in a non-negative real number in .
for length units
For any length units and , the product of the ratio of to and the ratio of to is equal to the ratio of to . Mathematically, this is expressed as , where the division denotes the ratio of the underlying scales of the length units, treated here as real numbers.
for positive
For any length unit and any positive real number (where ), the ratio of the unit scaled by to the original unit is equal to . Mathematically, this is expressed as: where the division denotes the ratio of the underlying scales of the length units, resulting in a non-negative real number .
for length units
Let be a length unit (an element of `LengthUnit`) and be a positive real number (). The ratio of the length unit to the scaled unit is equal to the reciprocal of the scaling factor, : In this expression, the division of length units and the resulting value are treated as non-negative real numbers in .
Let be a length unit (an element of `LengthUnit`, which corresponds to the set of positive real numbers ). Scaling the length unit by a factor of results in the original unit :
Let and be length units (elements of `LengthUnit`, which corresponds to the set of positive real numbers ). For any two positive real numbers such that and , the ratio of the scaled unit to the scaled unit is equal to the product of the ratio of the scaling factors and the ratio of the original units : Here, the division of length units and the scaling factors are treated as non-negative real numbers in .
Let be a length unit (an element of `LengthUnit`, which corresponds to the set of positive real numbers ). For any two positive real numbers such that and , scaling the unit by and then scaling the resulting unit by is equivalent to scaling the original unit by the product :
The length unit "meters" ()
The length unit "meters" is defined as the element of the type `LengthUnit` (which represents the set of positive real numbers ) that corresponds to the value . This serves as the base reference unit from which other length units are scaled.
The length unit of femtometers ( m)
The length unit "femtometers" is defined as an element of the type `LengthUnit`, which represents the set of positive real numbers . It is obtained by scaling the base unit `meters` by a factor of . In the underlying representation where one meter is assigned the value , a femtometer corresponds to the value .
The length unit of picometers ( m)
The length unit "picometers" is defined as an element of the type `LengthUnit`, which represents the set of positive real numbers . It is obtained by scaling the base unit `meters` by a factor of . In the underlying representation where one meter is assigned the value , a picometer corresponds to the value .
The length unit of nanometers ( m)
The length unit "nanometers" is defined as an element of the type `LengthUnit`, which represents the set of positive real numbers . It is obtained by scaling the base unit `meters` by a factor of . In the underlying representation where one meter is assigned the value , a nanometer corresponds to the value .
The length unit of micrometers ( m)
The length unit "micrometers" is an element of the type `LengthUnit` (representing the set of positive real numbers ) defined by scaling the base unit `meters` by a factor of . It corresponds to the value in the underlying representation where `meters` is assigned the value .
The length unit of millimeters ( m)
The length unit "millimeters" is an element of the type `LengthUnit` (which represents the set of positive real numbers ) defined by scaling the base unit `meters` by a factor of . It corresponds to the value in the underlying representation where one meter is assigned the value .
The length unit of centimeters ( m)
The length unit "centimeters" is an element of the type `LengthUnit` (representing the set of positive real numbers ) defined by scaling the base unit `meters` by a factor of , or . It corresponds to the value in the underlying representation where `meters` is assigned the value .
The length unit of inches ( m)
The length unit "inches" is an element of the type `LengthUnit` (representing the set of positive real numbers ) defined by scaling the base unit `meters` by a factor of . It corresponds to the value in the underlying representation where `meters` is assigned the value .
The length unit of links ( m)
The length unit "links" is defined as an element of the type `LengthUnit` (representing the set of positive real numbers ) obtained by scaling the base unit "meters" by a factor of .
The length unit "feet" ( meters)
The length unit "feet" is defined as an element of the type `LengthUnit` (representing the set of positive real numbers ) obtained by scaling the base unit "meters" by a factor of . In the underlying representation where "meters" corresponds to the value , "feet" corresponds to the value .
The length unit "yards" ( meters)
The length unit "yards" is defined as an element of the type `LengthUnit` (representing the set of positive real numbers ) obtained by scaling the base unit "meters" by a factor of .
Length unit of rods ( meters)
The length unit "rods" is defined as the element of the type `LengthUnit` (representing the set of positive real numbers ) obtained by scaling the reference unit "meters" by a factor of . In the underlying representation of length units as positive reals, this corresponds to the value .
Length unit of chains ( meters)
The length unit "chains" is defined as the element of the type `LengthUnit` (representing the set of positive real numbers ) obtained by scaling the reference unit "meters" by a factor of . In the underlying representation where "meters" corresponds to , "chains" corresponds to the value .
Length unit of furlongs ( meters)
The length unit "furlongs" is defined as the element of the type `LengthUnit` (which represents the set of positive real numbers ) obtained by scaling the reference unit "meters" by a factor of . In the underlying representation of length units as positive reals, this corresponds to the value .
Length unit of kilometers ( meters)
The length unit "kilometers" is defined as the element of the type `LengthUnit` (representing the set of positive real numbers ) obtained by scaling the reference unit "meters" by a factor of . In the underlying representation where "meters" corresponds to , "kilometers" corresponds to the value .
Length unit of miles ()
The length unit "miles" is defined as the element of the type `LengthUnit` (representing the set of positive real numbers ) obtained by scaling the reference unit "meters" by a factor of . In the underlying representation where "meters" corresponds to the value , "miles" corresponds to the value .
The length unit "nautical miles" ()
The length unit "nautical miles" is defined as the element of the type `LengthUnit` (representing the set of positive real numbers ) obtained by scaling the reference unit "meters" by a factor of . In the underlying representation where "meters" corresponds to the value , "nautical miles" corresponds to the value .
The length unit "astronomical units" ()
The length unit "astronomical units" is defined as the scaling of the base unit "meters" by a factor of . Within the `LengthUnit` type, which represents the set of positive real numbers (where "meters" corresponds to the value ), this unit corresponds to the value .
The length unit "light years" ()
The length unit "light years" is defined as the scaling of the base unit "meters" by a factor of . Within the `LengthUnit` type, which represents positive real numbers , this unit corresponds to the value .
The length unit "parsecs" ()
The length unit "parsecs" is defined as the scaling of the unit "astronomical units" by a factor of . Within the `LengthUnit` type, which represents the set of positive real numbers (where the unit "meters" corresponds to the value ), this unit represents the value of a parsec relative to the base meter, calculated by multiplying the value of an astronomical unit () by .
The ratio of the length unit `miles` to the length unit `yards` is equal to in the non-negative real numbers . This represents the fact that there are exactly 1760 yards in a mile.
There are exactly 220 yards in a furlong. Formally, the ratio of the length unit "furlongs" to the length unit "yards" is equal to the non-negative real number 220, denoted as .
