Metamath Proof Explorer


Theorem lcmn0val

Description: The value of the lcm operator when both operands are nonzero. (Contributed by Steve Rodriguez, 20-Jan-2020) (Revised by AV, 16-Sep-2020)

Ref Expression
Assertion lcmn0val
|- ( ( ( M e. ZZ /\ N e. ZZ ) /\ -. ( M = 0 \/ N = 0 ) ) -> ( M lcm N ) = inf ( { n e. NN | ( M || n /\ N || n ) } , RR , < ) )

Proof

Step Hyp Ref Expression
1 lcmval
 |-  ( ( M e. ZZ /\ N e. ZZ ) -> ( M lcm N ) = if ( ( M = 0 \/ N = 0 ) , 0 , inf ( { n e. NN | ( M || n /\ N || n ) } , RR , < ) ) )
2 iffalse
 |-  ( -. ( M = 0 \/ N = 0 ) -> if ( ( M = 0 \/ N = 0 ) , 0 , inf ( { n e. NN | ( M || n /\ N || n ) } , RR , < ) ) = inf ( { n e. NN | ( M || n /\ N || n ) } , RR , < ) )
3 1 2 sylan9eq
 |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ -. ( M = 0 \/ N = 0 ) ) -> ( M lcm N ) = inf ( { n e. NN | ( M || n /\ N || n ) } , RR , < ) )