Table 1. Symbols used in the model with description.

Symbol	Description
lc	Low copy number plasmid with conjugation ability
ln	Low copy number plasmid without conjugation ability
hc	High copy number plasmid with conjugation ability
hn	High copy number plasmid without conjugation ability
x 0	Frequency of plasmid free cell
xi	Frequency of cell infected by plasmid type i *
xm	Frequency of cell infected by multiple types of plasmid
r 0	Intrinsic growth rate of plasmid free cell
ri	Intrinsic growth rate of cell infected by plasmid type i
rm	Intrinsic growth rate of cell infected by multiple types of plasmid
gi	Fitness of plasmid of type i
pi	Frequency of plasmid of type i in host cell with multiple infection
φ	Cost paid by the host for the fitness of plasmid
λ	Cost of conjugation for the host
μ	Cost of conjugal efficiency for the plasmid
δ	Additive fitness due to extra copy number of the plasmid
ε	Rate of plasmid curing
βl	Conjugation frequency of the low copy number plasmid (lc)
βh	Conjugation frequency of the high copy number plasmid (hc)

*i ∈ lc, ln, hc, hn.