Libor Market Model is a model where Libor forwards have log-normal distribution in their’s respective probability measures (called T-measure)

example of Libor Market Model with just 2 forwards:

is a price at time t of zero-coupon bond paying at

, maturity ]

lets take a numeraire=bond

in LMM forward measure de:

are usually correlated

this drift(t) can be calculated (idea :