From To
Several relations convert or change things, leading to a form:
They converted the boiler from coal to gas-fired.
He changed the appointment time from 6 pm to 8 pm.
He altered the setting from 6 volts to 7.3 volts
He went from sad to happy in seconds.
The flight from Dallas to Las Vegas took over two hours.
He moved from Arkansas to California.
He was promoted from captain to major.
The company was transformed from a small family company to a large public corporation.
The frequency varied between 90 and 120 kHz.
The thing that changes can be:
Object to object
State to state
Number to number
Value to value
Time to time (special case, as each relation has a time)
Location to location (each relation has a location – sometimes, if the relation involves movement, it needs two locations)
Relations have one place to store a value for time and location, and an object like setting has a singular value (it can have a range, but the range is considered as all existing at the one time). A relation has a single place for a parameter – the parameter can be an object group, but that has a different meaning.
These possibilities suggest we need an object which can stand in the place of the real object, and have two objects or values or states - a FromTo.
Then the prepositions "from" and "to" build a FromTo, as do the prepositions "from" and "to" in isolation, when used with the particular relations (indicating that if he flew to Dallas, he flew from somewhere. The relation carries the time, location and logical state information, so FromTo does not need to be a relation.
We end up with more unknowns, but these are known unknowns that we can speculate about.
Some things vary or fluctuate back and forth – we have a special type of FromTo which has two values, but no direction – we could call it BackAndForth.
The procedures that manipulate objects or values need to know what to do when they encounter a FromTo. We could use the MEANING operator between the FromTo and its two values – if we arrive at the FromTo, then both meanings are possible. The order is important.