S=(0,1)∪(1,2)∪(3,4)
T={0,1,2,3}
(1) infinitely many functions S→T
(2) infinitely many strictly increasing S→T
(3) #{continuous}≤120;(4) every continuous is differentiable
S has 3 components: I1=(0,1), I2=(1,2), I3=(3,4)
∣T∣=4,T finite (discrete)
(1) #{f:S→T}=4∣S∣,∣S∣=∞
⇒(1) TRUE
(2) x<y⇒f(x)<f(y),f(x)∈T
an increasing chain needs distinct values in T
x1<⋯<x5⇒f(x1)<⋯<f(x5)
needs 5 distinct values, but ∣T∣=4
#{increasing}=0 ⇒(2) FALSE
continuous⇒f constant on each connected component
connected image of connected set is connected
I1,I2,I3→4 choices each independently
#{continuous}=43=64
64≤120 ⇒(3) TRUE
(4) f constant on each component⇒f′=0
S open⇒every point interior⇒(4) TRUE
TRUE: (1), (3), (4)
(1), (3), (4)