The multiplication of past x future is a vector with the function:= known = f(changeable) [y=f(x)].
The vector is a timeline as a vector space of {t,d}(time,distance) , so distance is a function of time: d=f(t)

As changeable = f(states) it says the more states we have the more knowledge as known() is possible.
So a substitution: known = f(f(states))
legend: y(unknown -> known)[d:distance]
x(unchangeable -> changeable)[t:time]
variant:x(immutable -> mutable)[t:time]

• Past = [unchangeable,known]
• Future = [changeable,unknown]
• Present= [changeable,known],[t->0]
• BigBang= [unchangeable,unknown],[d->∞]

In physics, spacetime, also called the space-time continuum, is a mathematical model that fuses the three dimensions of space and the one dimension of time into a single four-dimensional continuum.