P. 118 of Theorem List - Intuitionistic Logic Explorer

Theorem List for Intuitionistic Logic Explorer - 11701-11800   *Has distinct variable group(s)

Type	Label	Description
Statement
Theorem	absvalsq2i 11701	Square of value of absolute value function. (Contributed by NM, 2-Oct-1999.)
|- A e. CC   =>    |- ( ( abs ` A ) ^ 2 ) = ( ( ( Re ` A ) ^ 2 ) + ( ( Im ` A ) ^ 2 ) )
Theorem	abscli 11702	Real closure of absolute value. (Contributed by NM, 2-Aug-1999.)
|- A e. CC   =>    |- ( abs ` A ) e. RR
Theorem	absge0i 11703	Absolute value is nonnegative. (Contributed by NM, 2-Aug-1999.)
|- A e. CC   =>    |- 0 <_ ( abs ` A )
Theorem	absval2i 11704	Value of absolute value function. Definition 10.36 of [Gleason] p. 133. (Contributed by NM, 2-Oct-1999.)
|- A e. CC   =>    |- ( abs ` A ) = ( sqr ` ( ( ( Re ` A ) ^ 2 ) + ( ( Im ` A ) ^ 2 ) ) )
Theorem	abs00i 11705	The absolute value of a number is zero iff the number is zero. Proposition 10-3.7(c) of [Gleason] p. 133. (Contributed by NM, 28-Jul-1999.)
|- A e. CC   =>    |- ( ( abs ` A ) = 0 <-> A = 0 )
Theorem	absgt0api 11706	The absolute value of a nonzero number is positive. Remark in [Apostol] p. 363. (Contributed by NM, 1-Oct-1999.)
|- A e. CC   =>    |- ( A # 0 <-> 0 < ( abs ` A ) )
Theorem	absnegi 11707	Absolute value of negative. (Contributed by NM, 2-Aug-1999.)
|- A e. CC   =>    |- ( abs ` -u A ) = ( abs ` A )
Theorem	abscji 11708	The absolute value of a number and its conjugate are the same. Proposition 10-3.7(b) of [Gleason] p. 133. (Contributed by NM, 2-Oct-1999.)
|- A e. CC   =>    |- ( abs ` ( * ` A ) ) = ( abs ` A )
Theorem	releabsi 11709	The real part of a number is less than or equal to its absolute value. Proposition 10-3.7(d) of [Gleason] p. 133. (Contributed by NM, 2-Oct-1999.)
|- A e. CC   =>    |- ( Re ` A ) <_ ( abs ` A )
Theorem	abssubi 11710	Swapping order of subtraction doesn't change the absolute value. Example of [Apostol] p. 363. (Contributed by NM, 1-Oct-1999.)
|- A e. CC   &    |- B e. CC   =>    |- ( abs ` ( A - B ) ) = ( abs ` ( B - A ) )
Theorem	absmuli 11711	Absolute value distributes over multiplication. Proposition 10-3.7(f) of [Gleason] p. 133. (Contributed by NM, 1-Oct-1999.)
|- A e. CC   &    |- B e. CC   =>    |- ( abs ` ( A x. B ) ) = ( ( abs ` A ) x. ( abs ` B ) )
Theorem	sqabsaddi 11712	Square of absolute value of sum. Proposition 10-3.7(g) of [Gleason] p. 133. (Contributed by NM, 2-Oct-1999.)
|- A e. CC   &    |- B e. CC   =>    |- ( ( abs ` ( A + B ) ) ^ 2 ) = ( ( ( ( abs ` A ) ^ 2 ) + ( ( abs ` B ) ^ 2 ) ) + ( 2 x. ( Re ` ( A x. ( * ` B ) ) ) ) )
Theorem	sqabssubi 11713	Square of absolute value of difference. (Contributed by Steve Rodriguez, 20-Jan-2007.)
|- A e. CC   &    |- B e. CC   =>    |- ( ( abs ` ( A - B ) ) ^ 2 ) = ( ( ( ( abs ` A ) ^ 2 ) + ( ( abs ` B ) ^ 2 ) ) - ( 2 x. ( Re ` ( A x. ( * ` B ) ) ) ) )
Theorem	absdivapzi 11714	Absolute value distributes over division. (Contributed by Jim Kingdon, 13-Aug-2021.)
|- A e. CC   &    |- B e. CC   =>    |- ( B # 0 -> ( abs ` ( A / B ) ) = ( ( abs ` A ) / ( abs ` B ) ) )
Theorem	abstrii 11715	Triangle inequality for absolute value. Proposition 10-3.7(h) of [Gleason] p. 133. This is Metamath 100 proof #91. (Contributed by NM, 2-Oct-1999.)
|- A e. CC   &    |- B e. CC   =>    |- ( abs ` ( A + B ) ) <_ ( ( abs ` A ) + ( abs ` B ) )
Theorem	abs3difi 11716	Absolute value of differences around common element. (Contributed by NM, 2-Oct-1999.)
|- A e. CC   &    |- B e. CC   &    |- C e. CC   =>    |- ( abs ` ( A - B ) ) <_ ( ( abs ` ( A - C ) ) + ( abs ` ( C - B ) ) )
Theorem	abs3lemi 11717	Lemma involving absolute value of differences. (Contributed by NM, 2-Oct-1999.)
|- A e. CC   &    |- B e. CC   &    |- C e. CC   &    |- D e. RR   =>    |- ( ( ( abs ` ( A - C ) ) < ( D / 2 ) /\ ( abs ` ( C - B ) ) < ( D / 2 ) ) -> ( abs ` ( A - B ) ) < D )
Theorem	rpsqrtcld 11718	The square root of a positive real is positive. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR+ )   =>    |- ( ph -> ( sqr ` A ) e. RR+ )
Theorem	sqrtgt0d 11719	The square root of a positive real is positive. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR+ )   =>    |- ( ph -> 0 < ( sqr ` A ) )
Theorem	absnidd 11720	A negative number is the negative of its own absolute value. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> A <_ 0 )   =>    |- ( ph -> ( abs ` A ) = -u A )
Theorem	leabsd 11721	A real number is less than or equal to its absolute value. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   =>    |- ( ph -> A <_ ( abs ` A ) )
Theorem	absred 11722	Absolute value of a real number. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   =>    |- ( ph -> ( abs ` A ) = ( sqr ` ( A ^ 2 ) ) )
Theorem	resqrtcld 11723	The square root of a nonnegative real is a real. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> 0 <_ A )   =>    |- ( ph -> ( sqr ` A ) e. RR )
Theorem	sqrtmsqd 11724	Square root of square. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> 0 <_ A )   =>    |- ( ph -> ( sqr ` ( A x. A ) ) = A )
Theorem	sqrtsqd 11725	Square root of square. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> 0 <_ A )   =>    |- ( ph -> ( sqr ` ( A ^ 2 ) ) = A )
Theorem	sqrtge0d 11726	The square root of a nonnegative real is nonnegative. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> 0 <_ A )   =>    |- ( ph -> 0 <_ ( sqr ` A ) )
Theorem	absidd 11727	A nonnegative number is its own absolute value. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> 0 <_ A )   =>    |- ( ph -> ( abs ` A ) = A )
Theorem	sqrtdivd 11728	Square root distributes over division. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> 0 <_ A )   &    |- ( ph -> B e. RR+ )   =>    |- ( ph -> ( sqr ` ( A / B ) ) = ( ( sqr ` A ) / ( sqr ` B ) ) )
Theorem	sqrtmuld 11729	Square root distributes over multiplication. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> 0 <_ A )   &    |- ( ph -> B e. RR )   &    |- ( ph -> 0 <_ B )   =>    |- ( ph -> ( sqr ` ( A x. B ) ) = ( ( sqr ` A ) x. ( sqr ` B ) ) )
Theorem	sqrtsq2d 11730	Relationship between square root and squares. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> 0 <_ A )   &    |- ( ph -> B e. RR )   &    |- ( ph -> 0 <_ B )   =>    |- ( ph -> ( ( sqr ` A ) = B <-> A = ( B ^ 2 ) ) )
Theorem	sqrtled 11731	Square root is monotonic. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> 0 <_ A )   &    |- ( ph -> B e. RR )   &    |- ( ph -> 0 <_ B )   =>    |- ( ph -> ( A <_ B <-> ( sqr ` A ) <_ ( sqr ` B ) ) )
Theorem	sqrtltd 11732	Square root is strictly monotonic. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> 0 <_ A )   &    |- ( ph -> B e. RR )   &    |- ( ph -> 0 <_ B )   =>    |- ( ph -> ( A < B <-> ( sqr ` A ) < ( sqr ` B ) ) )
Theorem	sqr11d 11733	The square root function is one-to-one. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> 0 <_ A )   &    |- ( ph -> B e. RR )   &    |- ( ph -> 0 <_ B )   &    |- ( ph -> ( sqr ` A ) = ( sqr ` B ) )   =>    |- ( ph -> A = B )
Theorem	absltd 11734	Absolute value and 'less than' relation. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> B e. RR )   =>    |- ( ph -> ( ( abs ` A ) < B <-> ( -u B < A /\ A < B ) ) )
Theorem	absled 11735	Absolute value and 'less than or equal to' relation. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> B e. RR )   =>    |- ( ph -> ( ( abs ` A ) <_ B <-> ( -u B <_ A /\ A <_ B ) ) )
Theorem	abssubge0d 11736	Absolute value of a nonnegative difference. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> B e. RR )   &    |- ( ph -> A <_ B )   =>    |- ( ph -> ( abs ` ( B - A ) ) = ( B - A ) )
Theorem	abssuble0d 11737	Absolute value of a nonpositive difference. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> B e. RR )   &    |- ( ph -> A <_ B )   =>    |- ( ph -> ( abs ` ( A - B ) ) = ( B - A ) )
Theorem	absdifltd 11738	The absolute value of a difference and 'less than' relation. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> B e. RR )   &    |- ( ph -> C e. RR )   =>    |- ( ph -> ( ( abs ` ( A - B ) ) < C <-> ( ( B - C ) < A /\ A < ( B + C ) ) ) )
Theorem	absdifled 11739	The absolute value of a difference and 'less than or equal to' relation. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. RR )   &    |- ( ph -> B e. RR )   &    |- ( ph -> C e. RR )   =>    |- ( ph -> ( ( abs ` ( A - B ) ) <_ C <-> ( ( B - C ) <_ A /\ A <_ ( B + C ) ) ) )
Theorem	icodiamlt 11740	Two elements in a half-open interval have separation strictly less than the difference between the endpoints. (Contributed by Stefan O'Rear, 12-Sep-2014.)
|- ( ( ( A e. RR /\ B e. RR ) /\ ( C e. ( A [,) B ) /\ D e. ( A [,) B ) ) ) -> ( abs ` ( C - D ) ) < ( B - A ) )
Theorem	abscld 11741	Real closure of absolute value. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> ( abs ` A ) e. RR )
Theorem	absvalsqd 11742	Square of value of absolute value function. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> ( ( abs ` A ) ^ 2 ) = ( A x. ( * ` A ) ) )
Theorem	absvalsq2d 11743	Square of value of absolute value function. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> ( ( abs ` A ) ^ 2 ) = ( ( ( Re ` A ) ^ 2 ) + ( ( Im ` A ) ^ 2 ) ) )
Theorem	absge0d 11744	Absolute value is nonnegative. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> 0 <_ ( abs ` A ) )
Theorem	absval2d 11745	Value of absolute value function. Definition 10.36 of [Gleason] p. 133. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> ( abs ` A ) = ( sqr ` ( ( ( Re ` A ) ^ 2 ) + ( ( Im ` A ) ^ 2 ) ) ) )
Theorem	abs00d 11746	The absolute value of a number is zero iff the number is zero. Proposition 10-3.7(c) of [Gleason] p. 133. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   &    |- ( ph -> ( abs ` A ) = 0 )   =>    |- ( ph -> A = 0 )
Theorem	absne0d 11747	The absolute value of a number is zero iff the number is zero. Proposition 10-3.7(c) of [Gleason] p. 133. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   &    |- ( ph -> A =/= 0 )   =>    |- ( ph -> ( abs ` A ) =/= 0 )
Theorem	absrpclapd 11748	The absolute value of a complex number apart from zero is a positive real. (Contributed by Jim Kingdon, 13-Aug-2021.)
|- ( ph -> A e. CC )   &    |- ( ph -> A # 0 )   =>    |- ( ph -> ( abs ` A ) e. RR+ )
Theorem	absnegd 11749	Absolute value of negative. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> ( abs ` -u A ) = ( abs ` A ) )
Theorem	abscjd 11750	The absolute value of a number and its conjugate are the same. Proposition 10-3.7(b) of [Gleason] p. 133. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> ( abs ` ( * ` A ) ) = ( abs ` A ) )
Theorem	releabsd 11751	The real part of a number is less than or equal to its absolute value. Proposition 10-3.7(d) of [Gleason] p. 133. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> ( Re ` A ) <_ ( abs ` A ) )
Theorem	absexpd 11752	Absolute value of positive integer exponentiation. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   &    |- ( ph -> N e. NN0 )   =>    |- ( ph -> ( abs ` ( A ^ N ) ) = ( ( abs ` A ) ^ N ) )
Theorem	abssubd 11753	Swapping order of subtraction doesn't change the absolute value. Example of [Apostol] p. 363. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   &    |- ( ph -> B e. CC )   =>    |- ( ph -> ( abs ` ( A - B ) ) = ( abs ` ( B - A ) ) )
Theorem	absmuld 11754	Absolute value distributes over multiplication. Proposition 10-3.7(f) of [Gleason] p. 133. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   &    |- ( ph -> B e. CC )   =>    |- ( ph -> ( abs ` ( A x. B ) ) = ( ( abs ` A ) x. ( abs ` B ) ) )
Theorem	absdivapd 11755	Absolute value distributes over division. (Contributed by Jim Kingdon, 13-Aug-2021.)
|- ( ph -> A e. CC )   &    |- ( ph -> B e. CC )   &    |- ( ph -> B # 0 )   =>    |- ( ph -> ( abs ` ( A / B ) ) = ( ( abs ` A ) / ( abs ` B ) ) )
Theorem	abstrid 11756	Triangle inequality for absolute value. Proposition 10-3.7(h) of [Gleason] p. 133. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   &    |- ( ph -> B e. CC )   =>    |- ( ph -> ( abs ` ( A + B ) ) <_ ( ( abs ` A ) + ( abs ` B ) ) )
Theorem	abs2difd 11757	Difference of absolute values. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   &    |- ( ph -> B e. CC )   =>    |- ( ph -> ( ( abs ` A ) - ( abs ` B ) ) <_ ( abs ` ( A - B ) ) )
Theorem	abs2dif2d 11758	Difference of absolute values. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   &    |- ( ph -> B e. CC )   =>    |- ( ph -> ( abs ` ( A - B ) ) <_ ( ( abs ` A ) + ( abs ` B ) ) )
Theorem	abs2difabsd 11759	Absolute value of difference of absolute values. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   &    |- ( ph -> B e. CC )   =>    |- ( ph -> ( abs ` ( ( abs ` A ) - ( abs ` B ) ) ) <_ ( abs ` ( A - B ) ) )
Theorem	abs3difd 11760	Absolute value of differences around common element. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   &    |- ( ph -> B e. CC )   &    |- ( ph -> C e. CC )   =>    |- ( ph -> ( abs ` ( A - B ) ) <_ ( ( abs ` ( A - C ) ) + ( abs ` ( C - B ) ) ) )
Theorem	abs3lemd 11761	Lemma involving absolute value of differences. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> A e. CC )   &    |- ( ph -> B e. CC )   &    |- ( ph -> C e. CC )   &    |- ( ph -> D e. RR )   &    |- ( ph -> ( abs ` ( A - C ) ) < ( D / 2 ) )   &    |- ( ph -> ( abs ` ( C - B ) ) < ( D / 2 ) )   =>    |- ( ph -> ( abs ` ( A - B ) ) < D )
Theorem	qdenre 11762*	The rational numbers are dense in RR: any real number can be approximated with arbitrary precision by a rational number. For order theoretic density, see qbtwnre 10515. (Contributed by BJ, 15-Oct-2021.)
|- ( ( A e. RR /\ B e. RR+ ) -> E. x e. QQ ( abs ` ( x - A ) ) < B )
4.8.5  The maximum of two real numbers
Theorem	maxcom 11763	The maximum of two reals is commutative. Lemma 3.9 of [Geuvers], p. 10. (Contributed by Jim Kingdon, 21-Dec-2021.)
|- sup ( { A , B } , RR , < ) = sup ( { B , A } , RR , < )
Theorem	maxabsle 11764	An upper bound for { A , B }. (Contributed by Jim Kingdon, 20-Dec-2021.)
|- ( ( A e. RR /\ B e. RR ) -> A <_ ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) )
Theorem	maxleim 11765	Value of maximum when we know which number is larger. (Contributed by Jim Kingdon, 21-Dec-2021.)
|- ( ( A e. RR /\ B e. RR ) -> ( A <_ B -> sup ( { A , B } , RR , < ) = B ) )
Theorem	maxabslemab 11766	Lemma for maxabs 11769. A variation of maxleim 11765- that is, if we know which of two real numbers is larger, we know the maximum of the two. (Contributed by Jim Kingdon, 21-Dec-2021.)
|- ( ph -> A e. RR )   &    |- ( ph -> B e. RR )   &    |- ( ph -> A < B )   =>    |- ( ph -> ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) = B )
Theorem	maxabslemlub 11767	Lemma for maxabs 11769. A least upper bound for { A , B }. (Contributed by Jim Kingdon, 20-Dec-2021.)
|- ( ph -> A e. RR )   &    |- ( ph -> B e. RR )   &    |- ( ph -> C e. RR )   &    |- ( ph -> C < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) )   =>    |- ( ph -> ( C < A \/ C < B ) )
Theorem	maxabslemval 11768*	Lemma for maxabs 11769. Value of the supremum. (Contributed by Jim Kingdon, 22-Dec-2021.)
|- ( ( A e. RR /\ B e. RR ) -> ( ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) e. RR /\ A. x e. { A , B } -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < x /\ A. x e. RR ( x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) -> E. z e. { A , B } x < z ) ) )
Theorem	maxabs 11769	Maximum of two real numbers in terms of absolute value. (Contributed by Jim Kingdon, 20-Dec-2021.)
|- ( ( A e. RR /\ B e. RR ) -> sup ( { A , B } , RR , < ) = ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) )
Theorem	maxcl 11770	The maximum of two real numbers is a real number. (Contributed by Jim Kingdon, 22-Dec-2021.)
|- ( ( A e. RR /\ B e. RR ) -> sup ( { A , B } , RR , < ) e. RR )
Theorem	maxle1 11771	The maximum of two reals is no smaller than the first real. Lemma 3.10 of [Geuvers], p. 10. (Contributed by Jim Kingdon, 21-Dec-2021.)
|- ( ( A e. RR /\ B e. RR ) -> A <_ sup ( { A , B } , RR , < ) )
Theorem	maxle2 11772	The maximum of two reals is no smaller than the second real. Lemma 3.10 of [Geuvers], p. 10. (Contributed by Jim Kingdon, 21-Dec-2021.)
|- ( ( A e. RR /\ B e. RR ) -> B <_ sup ( { A , B } , RR , < ) )
Theorem	maxleast 11773	The maximum of two reals is a least upper bound. Lemma 3.11 of [Geuvers], p. 10. (Contributed by Jim Kingdon, 22-Dec-2021.)
|- ( ( ( A e. RR /\ B e. RR /\ C e. RR ) /\ ( A <_ C /\ B <_ C ) ) -> sup ( { A , B } , RR , < ) <_ C )
Theorem	maxleastb 11774	Two ways of saying the maximum of two numbers is less than or equal to a third. (Contributed by Jim Kingdon, 31-Jan-2022.)
|- ( ( A e. RR /\ B e. RR /\ C e. RR ) -> ( sup ( { A , B } , RR , < ) <_ C <-> ( A <_ C /\ B <_ C ) ) )
Theorem	maxleastlt 11775	The maximum as a least upper bound, in terms of less than. (Contributed by Jim Kingdon, 9-Feb-2022.)
|- ( ( ( A e. RR /\ B e. RR ) /\ ( C e. RR /\ C < sup ( { A , B } , RR , < ) ) ) -> ( C < A \/ C < B ) )
Theorem	maxleb 11776	Equivalence of <_ and being equal to the maximum of two reals. Lemma 3.12 of [Geuvers], p. 10. (Contributed by Jim Kingdon, 21-Dec-2021.)
|- ( ( A e. RR /\ B e. RR ) -> ( A <_ B <-> sup ( { A , B } , RR , < ) = B ) )
Theorem	dfabsmax 11777	Absolute value of a real number in terms of maximum. Definition 3.13 of [Geuvers], p. 11. (Contributed by BJ and Jim Kingdon, 21-Dec-2021.)
|- ( A e. RR -> ( abs ` A ) = sup ( { A , -u A } , RR , < ) )
Theorem	maxltsup 11778	Two ways of saying the maximum of two numbers is less than a third. (Contributed by Jim Kingdon, 10-Feb-2022.)
|- ( ( A e. RR /\ B e. RR /\ C e. RR ) -> ( sup ( { A , B } , RR , < ) < C <-> ( A < C /\ B < C ) ) )
Theorem	max0addsup 11779	The sum of the positive and negative part functions is the absolute value function over the reals. (Contributed by Jim Kingdon, 30-Jan-2022.)
|- ( A e. RR -> ( sup ( { A , 0 } , RR , < ) + sup ( { -u A , 0 } , RR , < ) ) = ( abs ` A ) )
Theorem	rexanre 11780*	Combine two different upper real properties into one. (Contributed by Mario Carneiro, 8-May-2016.)
|- ( A C_ RR -> ( E. j e. RR A. k e. A ( j <_ k -> ( ph /\ ps ) ) <-> ( E. j e. RR A. k e. A ( j <_ k -> ph ) /\ E. j e. RR A. k e. A ( j <_ k -> ps ) ) ) )
Theorem	rexico 11781*	Restrict the base of an upper real quantifier to an upper real set. (Contributed by Mario Carneiro, 12-May-2016.)
|- ( ( A C_ RR /\ B e. RR ) -> ( E. j e. ( B [,) +oo ) A. k e. A ( j <_ k -> ph ) <-> E. j e. RR A. k e. A ( j <_ k -> ph ) ) )
Theorem	maxclpr 11782	The maximum of two real numbers is one of those numbers if and only if dichotomy ( A <_ B \/ B <_ A) holds. For example, this can be combined with zletric 9522 if one is dealing with integers, but real number dichotomy in general does not follow from our axioms. (Contributed by Jim Kingdon, 1-Feb-2022.)
|- ( ( A e. RR /\ B e. RR ) -> ( sup ( { A , B } , RR , < ) e. { A , B } <-> ( A <_ B \/ B <_ A ) ) )
Theorem	rpmaxcl 11783	The maximum of two positive real numbers is a positive real number. (Contributed by Jim Kingdon, 10-Nov-2023.)
|- ( ( A e. RR+ /\ B e. RR+ ) -> sup ( { A , B } , RR , < ) e. RR+ )
Theorem	zmaxcl 11784	The maximum of two integers is an integer. (Contributed by Jim Kingdon, 27-Sep-2022.)
|- ( ( A e. ZZ /\ B e. ZZ ) -> sup ( { A , B } , RR , < ) e. ZZ )
Theorem	nn0maxcl 11785	The maximum of two nonnegative integers is a nonnegative integer. (Contributed by Jim Kingdon, 28-Oct-2025.)
|- ( ( A e. NN0 /\ B e. NN0 ) -> sup ( { A , B } , RR , < ) e. NN0 )
Theorem	2zsupmax 11786	Two ways to express the maximum of two integers. Because order of integers is decidable, we have more flexibility than for real numbers. (Contributed by Jim Kingdon, 22-Jan-2023.)
|- ( ( A e. ZZ /\ B e. ZZ ) -> sup ( { A , B } , RR , < ) = if ( A <_ B , B , A ) )
Theorem	fimaxre2 11787*	A nonempty finite set of real numbers has an upper bound. (Contributed by Jeff Madsen, 27-May-2011.) (Revised by Mario Carneiro, 13-Feb-2014.)
|- ( ( A C_ RR /\ A e. Fin ) -> E. x e. RR A. y e. A y <_ x )
Theorem	negfi 11788*	The negation of a finite set of real numbers is finite. (Contributed by AV, 9-Aug-2020.)
|- ( ( A C_ RR /\ A e. Fin ) -> { n e. RR | -u n e. A } e. Fin )
4.8.6  The minimum of two real numbers
Theorem	mincom 11789	The minimum of two reals is commutative. (Contributed by Jim Kingdon, 8-Feb-2021.)
|- inf ( { A , B } , RR , < ) = inf ( { B , A } , RR , < )
Theorem	minmax 11790	Minimum expressed in terms of maximum. (Contributed by Jim Kingdon, 8-Feb-2021.)
|- ( ( A e. RR /\ B e. RR ) -> inf ( { A , B } , RR , < ) = -u sup ( { -u A , -u B } , RR , < ) )
Theorem	mincl 11791	The minumum of two real numbers is a real number. (Contributed by Jim Kingdon, 25-Apr-2023.)
|- ( ( A e. RR /\ B e. RR ) -> inf ( { A , B } , RR , < ) e. RR )
Theorem	min1inf 11792	The minimum of two numbers is less than or equal to the first. (Contributed by Jim Kingdon, 8-Feb-2021.)
|- ( ( A e. RR /\ B e. RR ) -> inf ( { A , B } , RR , < ) <_ A )
Theorem	min2inf 11793	The minimum of two numbers is less than or equal to the second. (Contributed by Jim Kingdon, 9-Feb-2021.)
|- ( ( A e. RR /\ B e. RR ) -> inf ( { A , B } , RR , < ) <_ B )
Theorem	lemininf 11794	Two ways of saying a number is less than or equal to the minimum of two others. (Contributed by NM, 3-Aug-2007.)
|- ( ( A e. RR /\ B e. RR /\ C e. RR ) -> ( A <_ inf ( { B , C } , RR , < ) <-> ( A <_ B /\ A <_ C ) ) )
Theorem	ltmininf 11795	Two ways of saying a number is less than the minimum of two others. (Contributed by Jim Kingdon, 10-Feb-2022.)
|- ( ( A e. RR /\ B e. RR /\ C e. RR ) -> ( A < inf ( { B , C } , RR , < ) <-> ( A < B /\ A < C ) ) )
Theorem	minabs 11796	The minimum of two real numbers in terms of absolute value. (Contributed by Jim Kingdon, 15-May-2023.)
|- ( ( A e. RR /\ B e. RR ) -> inf ( { A , B } , RR , < ) = ( ( ( A + B ) - ( abs ` ( A - B ) ) ) / 2 ) )
Theorem	minclpr 11797	The minimum of two real numbers is one of those numbers if and only if dichotomy ( A <_ B \/ B <_ A) holds. For example, this can be combined with zletric 9522 if one is dealing with integers, but real number dichotomy in general does not follow from our axioms. (Contributed by Jim Kingdon, 23-May-2023.)
|- ( ( A e. RR /\ B e. RR ) -> (inf ( { A , B } , RR , < ) e. { A , B } <-> ( A <_ B \/ B <_ A ) ) )
Theorem	rpmincl 11798	The minumum of two positive real numbers is a positive real number. (Contributed by Jim Kingdon, 25-Apr-2023.)
|- ( ( A e. RR+ /\ B e. RR+ ) -> inf ( { A , B } , RR , < ) e. RR+ )
Theorem	bdtrilem 11799	Lemma for bdtri 11800. (Contributed by Steven Nguyen and Jim Kingdon, 17-May-2023.)
|- ( ( ( A e. RR /\ 0 <_ A ) /\ ( B e. RR /\ 0 <_ B ) /\ C e. RR+ ) -> ( ( abs ` ( A - C ) ) + ( abs ` ( B - C ) ) ) <_ ( C + ( abs ` ( ( A + B ) - C ) ) ) )
Theorem	bdtri 11800	Triangle inequality for bounded values. (Contributed by Jim Kingdon, 15-May-2023.)
|- ( ( ( A e. RR /\ 0 <_ A ) /\ ( B e. RR /\ 0 <_ B ) /\ C e. RR+ ) -> inf ( { ( A + B ) , C } , RR , < ) <_ (inf ( { A , C } , RR , < ) + inf ( { B , C } , RR , < ) ) )