P. 95 of Theorem List - Intuitionistic Logic Explorer

Theorem List for Intuitionistic Logic Explorer - 9401-9500   *Has distinct variable group(s)

Type	Label	Description
Statement
Theorem	nnlem1lt 9401	Positive integer ordering relation. (Contributed by NM, 21-Jun-2005.)
|- ( ( M e. NN /\ N e. NN ) -> ( M <_ N <-> ( M - 1 ) < N ) )
Theorem	nnltlem1 9402	Positive integer ordering relation. (Contributed by NM, 21-Jun-2005.)
|- ( ( M e. NN /\ N e. NN ) -> ( M < N <-> M <_ ( N - 1 ) ) )
Theorem	nnm1ge0 9403	A positive integer decreased by 1 is greater than or equal to 0. (Contributed by AV, 30-Oct-2018.)
|- ( N e. NN -> 0 <_ ( N - 1 ) )
Theorem	nn0ge0div 9404	Division of a nonnegative integer by a positive number is not negative. (Contributed by Alexander van der Vekens, 14-Apr-2018.)
|- ( ( K e. NN0 /\ L e. NN ) -> 0 <_ ( K / L ) )
Theorem	zdiv 9405*	Two ways to express " M divides N. (Contributed by NM, 3-Oct-2008.)
|- ( ( M e. NN /\ N e. ZZ ) -> ( E. k e. ZZ ( M x. k ) = N <-> ( N / M ) e. ZZ ) )
Theorem	zdivadd 9406	Property of divisibility: if D divides A and B then it divides A + B. (Contributed by NM, 3-Oct-2008.)
|- ( ( ( D e. NN /\ A e. ZZ /\ B e. ZZ ) /\ ( ( A / D ) e. ZZ /\ ( B / D ) e. ZZ ) ) -> ( ( A + B ) / D ) e. ZZ )
Theorem	zdivmul 9407	Property of divisibility: if D divides A then it divides B x. A. (Contributed by NM, 3-Oct-2008.)
|- ( ( ( D e. NN /\ A e. ZZ /\ B e. ZZ ) /\ ( A / D ) e. ZZ ) -> ( ( B x. A ) / D ) e. ZZ )
Theorem	zextle 9408*	An extensionality-like property for integer ordering. (Contributed by NM, 29-Oct-2005.)
|- ( ( M e. ZZ /\ N e. ZZ /\ A. k e. ZZ ( k <_ M <-> k <_ N ) ) -> M = N )
Theorem	zextlt 9409*	An extensionality-like property for integer ordering. (Contributed by NM, 29-Oct-2005.)
|- ( ( M e. ZZ /\ N e. ZZ /\ A. k e. ZZ ( k < M <-> k < N ) ) -> M = N )
Theorem	recnz 9410	The reciprocal of a number greater than 1 is not an integer. (Contributed by NM, 3-May-2005.)
|- ( ( A e. RR /\ 1 < A ) -> -. ( 1 / A ) e. ZZ )
Theorem	btwnnz 9411	A number between an integer and its successor is not an integer. (Contributed by NM, 3-May-2005.)
|- ( ( A e. ZZ /\ A < B /\ B < ( A + 1 ) ) -> -. B e. ZZ )
Theorem	gtndiv 9412	A larger number does not divide a smaller positive integer. (Contributed by NM, 3-May-2005.)
|- ( ( A e. RR /\ B e. NN /\ B < A ) -> -. ( B / A ) e. ZZ )
Theorem	halfnz 9413	One-half is not an integer. (Contributed by NM, 31-Jul-2004.)
|- -. ( 1 / 2 ) e. ZZ
Theorem	3halfnz 9414	Three halves is not an integer. (Contributed by AV, 2-Jun-2020.)
|- -. ( 3 / 2 ) e. ZZ
Theorem	suprzclex 9415*	The supremum of a set of integers is an element of the set. (Contributed by Jim Kingdon, 20-Dec-2021.)
|- ( ph -> E. x e. RR ( A. y e. A -. x < y /\ A. y e. RR ( y < x -> E. z e. A y < z ) ) )   &    |- ( ph -> A C_ ZZ )   =>    |- ( ph -> sup ( A , RR , < ) e. A )
Theorem	prime 9416*	Two ways to express " A is a prime number (or 1)". (Contributed by NM, 4-May-2005.)
|- ( A e. NN -> ( A. x e. NN ( ( A / x ) e. NN -> ( x = 1 \/ x = A ) ) <-> A. x e. NN ( ( 1 < x /\ x <_ A /\ ( A / x ) e. NN ) -> x = A ) ) )
Theorem	msqznn 9417	The square of a nonzero integer is a positive integer. (Contributed by NM, 2-Aug-2004.)
|- ( ( A e. ZZ /\ A =/= 0 ) -> ( A x. A ) e. NN )
Theorem	zneo 9418	No even integer equals an odd integer (i.e. no integer can be both even and odd). Exercise 10(a) of [Apostol] p. 28. (Contributed by NM, 31-Jul-2004.) (Proof shortened by Mario Carneiro, 18-May-2014.)
|- ( ( A e. ZZ /\ B e. ZZ ) -> ( 2 x. A ) =/= ( ( 2 x. B ) + 1 ) )
Theorem	nneoor 9419	A positive integer is even or odd. (Contributed by Jim Kingdon, 15-Mar-2020.)
|- ( N e. NN -> ( ( N / 2 ) e. NN \/ ( ( N + 1 ) / 2 ) e. NN ) )
Theorem	nneo 9420	A positive integer is even or odd but not both. (Contributed by NM, 1-Jan-2006.) (Proof shortened by Mario Carneiro, 18-May-2014.)
|- ( N e. NN -> ( ( N / 2 ) e. NN <-> -. ( ( N + 1 ) / 2 ) e. NN ) )
Theorem	nneoi 9421	A positive integer is even or odd but not both. (Contributed by NM, 20-Aug-2001.)
|- N e. NN   =>    |- ( ( N / 2 ) e. NN <-> -. ( ( N + 1 ) / 2 ) e. NN )
Theorem	zeo 9422	An integer is even or odd. (Contributed by NM, 1-Jan-2006.)
|- ( N e. ZZ -> ( ( N / 2 ) e. ZZ \/ ( ( N + 1 ) / 2 ) e. ZZ ) )
Theorem	zeo2 9423	An integer is even or odd but not both. (Contributed by Mario Carneiro, 12-Sep-2015.)
|- ( N e. ZZ -> ( ( N / 2 ) e. ZZ <-> -. ( ( N + 1 ) / 2 ) e. ZZ ) )
Theorem	peano2uz2 9424*	Second Peano postulate for upper integers. (Contributed by NM, 3-Oct-2004.)
|- ( ( A e. ZZ /\ B e. { x e. ZZ | A <_ x } ) -> ( B + 1 ) e. { x e. ZZ | A <_ x } )
Theorem	peano5uzti 9425*	Peano's inductive postulate for upper integers. (Contributed by NM, 6-Jul-2005.) (Revised by Mario Carneiro, 25-Jul-2013.)
|- ( N e. ZZ -> ( ( N e. A /\ A. x e. A ( x + 1 ) e. A ) -> { k e. ZZ | N <_ k } C_ A ) )
Theorem	peano5uzi 9426*	Peano's inductive postulate for upper integers. (Contributed by NM, 6-Jul-2005.) (Revised by Mario Carneiro, 3-May-2014.)
|- N e. ZZ   =>    |- ( ( N e. A /\ A. x e. A ( x + 1 ) e. A ) -> { k e. ZZ | N <_ k } C_ A )
Theorem	dfuzi 9427*	An expression for the upper integers that start at N that is analogous to dfnn2 8984 for positive integers. (Contributed by NM, 6-Jul-2005.) (Proof shortened by Mario Carneiro, 3-May-2014.)
|- N e. ZZ   =>    |- { z e. ZZ | N <_ z } = |^| { x | ( N e. x /\ A. y e. x ( y + 1 ) e. x ) }
Theorem	uzind 9428*	Induction on the upper integers that start at M. The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction step. (Contributed by NM, 5-Jul-2005.)
|- ( j = M -> ( ph <-> ps ) )   &    |- ( j = k -> ( ph <-> ch ) )   &    |- ( j = ( k + 1 ) -> ( ph <-> th ) )   &    |- ( j = N -> ( ph <-> ta ) )   &    |- ( M e. ZZ -> ps )   &    |- ( ( M e. ZZ /\ k e. ZZ /\ M <_ k ) -> ( ch -> th ) )   =>    |- ( ( M e. ZZ /\ N e. ZZ /\ M <_ N ) -> ta )
Theorem	uzind2 9429*	Induction on the upper integers that start after an integer M. The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction step. (Contributed by NM, 25-Jul-2005.)
|- ( j = ( M + 1 ) -> ( ph <-> ps ) )   &    |- ( j = k -> ( ph <-> ch ) )   &    |- ( j = ( k + 1 ) -> ( ph <-> th ) )   &    |- ( j = N -> ( ph <-> ta ) )   &    |- ( M e. ZZ -> ps )   &    |- ( ( M e. ZZ /\ k e. ZZ /\ M < k ) -> ( ch -> th ) )   =>    |- ( ( M e. ZZ /\ N e. ZZ /\ M < N ) -> ta )
Theorem	uzind3 9430*	Induction on the upper integers that start at an integer M. The first four hypotheses give us the substitution instances we need, and the last two are the basis and the induction step. (Contributed by NM, 26-Jul-2005.)
|- ( j = M -> ( ph <-> ps ) )   &    |- ( j = m -> ( ph <-> ch ) )   &    |- ( j = ( m + 1 ) -> ( ph <-> th ) )   &    |- ( j = N -> ( ph <-> ta ) )   &    |- ( M e. ZZ -> ps )   &    |- ( ( M e. ZZ /\ m e. { k e. ZZ | M <_ k } ) -> ( ch -> th ) )   =>    |- ( ( M e. ZZ /\ N e. { k e. ZZ | M <_ k } ) -> ta )
Theorem	nn0ind 9431*	Principle of Mathematical Induction (inference schema) on nonnegative integers. The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction step. (Contributed by NM, 13-May-2004.)
|- ( x = 0 -> ( ph <-> ps ) )   &    |- ( x = y -> ( ph <-> ch ) )   &    |- ( x = ( y + 1 ) -> ( ph <-> th ) )   &    |- ( x = A -> ( ph <-> ta ) )   &    |- ps   &    |- ( y e. NN0 -> ( ch -> th ) )   =>    |- ( A e. NN0 -> ta )
Theorem	fzind 9432*	Induction on the integers from M to N inclusive . The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction step. (Contributed by Paul Chapman, 31-Mar-2011.)
|- ( x = M -> ( ph <-> ps ) )   &    |- ( x = y -> ( ph <-> ch ) )   &    |- ( x = ( y + 1 ) -> ( ph <-> th ) )   &    |- ( x = K -> ( ph <-> ta ) )   &    |- ( ( M e. ZZ /\ N e. ZZ /\ M <_ N ) -> ps )   &    |- ( ( ( M e. ZZ /\ N e. ZZ ) /\ ( y e. ZZ /\ M <_ y /\ y < N ) ) -> ( ch -> th ) )   =>    |- ( ( ( M e. ZZ /\ N e. ZZ ) /\ ( K e. ZZ /\ M <_ K /\ K <_ N ) ) -> ta )
Theorem	fnn0ind 9433*	Induction on the integers from 0 to N inclusive . The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction step. (Contributed by Paul Chapman, 31-Mar-2011.)
|- ( x = 0 -> ( ph <-> ps ) )   &    |- ( x = y -> ( ph <-> ch ) )   &    |- ( x = ( y + 1 ) -> ( ph <-> th ) )   &    |- ( x = K -> ( ph <-> ta ) )   &    |- ( N e. NN0 -> ps )   &    |- ( ( N e. NN0 /\ y e. NN0 /\ y < N ) -> ( ch -> th ) )   =>    |- ( ( N e. NN0 /\ K e. NN0 /\ K <_ N ) -> ta )
Theorem	nn0ind-raph 9434*	Principle of Mathematical Induction (inference schema) on nonnegative integers. The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction step. Raph Levien remarks: "This seems a bit painful. I wonder if an explicit substitution version would be easier." (Contributed by Raph Levien, 10-Apr-2004.)
|- ( x = 0 -> ( ph <-> ps ) )   &    |- ( x = y -> ( ph <-> ch ) )   &    |- ( x = ( y + 1 ) -> ( ph <-> th ) )   &    |- ( x = A -> ( ph <-> ta ) )   &    |- ps   &    |- ( y e. NN0 -> ( ch -> th ) )   =>    |- ( A e. NN0 -> ta )
Theorem	zindd 9435*	Principle of Mathematical Induction on all integers, deduction version. The first five hypotheses give the substitutions; the last three are the basis, the induction, and the extension to negative numbers. (Contributed by Paul Chapman, 17-Apr-2009.) (Proof shortened by Mario Carneiro, 4-Jan-2017.)
|- ( x = 0 -> ( ph <-> ps ) )   &    |- ( x = y -> ( ph <-> ch ) )   &    |- ( x = ( y + 1 ) -> ( ph <-> ta ) )   &    |- ( x = -u y -> ( ph <-> th ) )   &    |- ( x = A -> ( ph <-> et ) )   &    |- ( ze -> ps )   &    |- ( ze -> ( y e. NN0 -> ( ch -> ta ) ) )   &    |- ( ze -> ( y e. NN -> ( ch -> th ) ) )   =>    |- ( ze -> ( A e. ZZ -> et ) )
Theorem	btwnz 9436*	Any real number can be sandwiched between two integers. Exercise 2 of [Apostol] p. 28. (Contributed by NM, 10-Nov-2004.)
|- ( A e. RR -> ( E. x e. ZZ x < A /\ E. y e. ZZ A < y ) )
Theorem	nn0zd 9437	A positive integer is an integer. (Contributed by Mario Carneiro, 28-May-2016.)
|- ( ph -> A e. NN0 )   =>    |- ( ph -> A e. ZZ )
Theorem	nnzd 9438	A nonnegative integer is an integer. (Contributed by Mario Carneiro, 28-May-2016.)
|- ( ph -> A e. NN )   =>    |- ( ph -> A e. ZZ )
Theorem	zred 9439	An integer is a real number. (Contributed by Mario Carneiro, 28-May-2016.)
|- ( ph -> A e. ZZ )   =>    |- ( ph -> A e. RR )
Theorem	zcnd 9440	An integer is a complex number. (Contributed by Mario Carneiro, 28-May-2016.)
|- ( ph -> A e. ZZ )   =>    |- ( ph -> A e. CC )
Theorem	znegcld 9441	Closure law for negative integers. (Contributed by Mario Carneiro, 28-May-2016.)
|- ( ph -> A e. ZZ )   =>    |- ( ph -> -u A e. ZZ )
Theorem	peano2zd 9442	Deduction from second Peano postulate generalized to integers. (Contributed by Mario Carneiro, 28-May-2016.)
|- ( ph -> A e. ZZ )   =>    |- ( ph -> ( A + 1 ) e. ZZ )
Theorem	zaddcld 9443	Closure of addition of integers. (Contributed by Mario Carneiro, 28-May-2016.)
|- ( ph -> A e. ZZ )   &    |- ( ph -> B e. ZZ )   =>    |- ( ph -> ( A + B ) e. ZZ )
Theorem	zsubcld 9444	Closure of subtraction of integers. (Contributed by Mario Carneiro, 28-May-2016.)
|- ( ph -> A e. ZZ )   &    |- ( ph -> B e. ZZ )   =>    |- ( ph -> ( A - B ) e. ZZ )
Theorem	zmulcld 9445	Closure of multiplication of integers. (Contributed by Mario Carneiro, 28-May-2016.)
|- ( ph -> A e. ZZ )   &    |- ( ph -> B e. ZZ )   =>    |- ( ph -> ( A x. B ) e. ZZ )
Theorem	zadd2cl 9446	Increasing an integer by 2 results in an integer. (Contributed by Alexander van der Vekens, 16-Sep-2018.)
|- ( N e. ZZ -> ( N + 2 ) e. ZZ )
Theorem	btwnapz 9447	A number between an integer and its successor is apart from any integer. (Contributed by Jim Kingdon, 6-Jan-2023.)
|- ( ph -> A e. ZZ )   &    |- ( ph -> B e. RR )   &    |- ( ph -> C e. ZZ )   &    |- ( ph -> A < B )   &    |- ( ph -> B < ( A + 1 ) )   =>    |- ( ph -> B # C )
4.4.10  Decimal arithmetic
Syntax	cdc 9448	Constant used for decimal constructor.
class ; A B
Definition	df-dec 9449	Define the "decimal constructor", which is used to build up "decimal integers" or "numeric terms" in base 1 0. For example, (;;; 1 0 0 0 + ;;; 2 0 0 0 ) = ;;; 3 0 0 0 1kp2ke3k 15216. (Contributed by Mario Carneiro, 17-Apr-2015.) (Revised by AV, 1-Aug-2021.)
|- ; A B = ( ( ( 9 + 1 ) x. A ) + B )
Theorem	9p1e10 9450	9 + 1 = 10. (Contributed by Mario Carneiro, 18-Apr-2015.) (Revised by Stanislas Polu, 7-Apr-2020.) (Revised by AV, 1-Aug-2021.)
|- ( 9 + 1 ) = ; 1 0
Theorem	dfdec10 9451	Version of the definition of the "decimal constructor" using ; 1 0 instead of the symbol 10. Of course, this statement cannot be used as definition, because it uses the "decimal constructor". (Contributed by AV, 1-Aug-2021.)
|- ; A B = ( (; 1 0 x. A ) + B )
Theorem	deceq1 9452	Equality theorem for the decimal constructor. (Contributed by Mario Carneiro, 17-Apr-2015.) (Revised by AV, 6-Sep-2021.)
|- ( A = B -> ; A C = ; B C )
Theorem	deceq2 9453	Equality theorem for the decimal constructor. (Contributed by Mario Carneiro, 17-Apr-2015.) (Revised by AV, 6-Sep-2021.)
|- ( A = B -> ; C A = ; C B )
Theorem	deceq1i 9454	Equality theorem for the decimal constructor. (Contributed by Mario Carneiro, 17-Apr-2015.)
|- A = B   =>    |- ; A C = ; B C
Theorem	deceq2i 9455	Equality theorem for the decimal constructor. (Contributed by Mario Carneiro, 17-Apr-2015.)
|- A = B   =>    |- ; C A = ; C B
Theorem	deceq12i 9456	Equality theorem for the decimal constructor. (Contributed by Mario Carneiro, 17-Apr-2015.)
|- A = B   &    |- C = D   =>    |- ; A C = ; B D
Theorem	numnncl 9457	Closure for a numeral (with units place). (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN0   &    |- A e. NN0   &    |- B e. NN   =>    |- ( ( T x. A ) + B ) e. NN
Theorem	num0u 9458	Add a zero in the units place. (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN0   &    |- A e. NN0   =>    |- ( T x. A ) = ( ( T x. A ) + 0 )
Theorem	num0h 9459	Add a zero in the higher places. (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN0   &    |- A e. NN0   =>    |- A = ( ( T x. 0 ) + A )
Theorem	numcl 9460	Closure for a decimal integer (with units place). (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN0   &    |- A e. NN0   &    |- B e. NN0   =>    |- ( ( T x. A ) + B ) e. NN0
Theorem	numsuc 9461	The successor of a decimal integer (no carry). (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN0   &    |- A e. NN0   &    |- B e. NN0   &    |- ( B + 1 ) = C   &    |- N = ( ( T x. A ) + B )   =>    |- ( N + 1 ) = ( ( T x. A ) + C )
Theorem	deccl 9462	Closure for a numeral. (Contributed by Mario Carneiro, 17-Apr-2015.) (Revised by AV, 6-Sep-2021.)
|- A e. NN0   &    |- B e. NN0   =>    |- ; A B e. NN0
Theorem	10nn 9463	10 is a positive integer. (Contributed by NM, 8-Nov-2012.) (Revised by AV, 6-Sep-2021.)
|- ; 1 0 e. NN
Theorem	10pos 9464	The number 10 is positive. (Contributed by NM, 5-Feb-2007.) (Revised by AV, 8-Sep-2021.)
|- 0 < ; 1 0
Theorem	10nn0 9465	10 is a nonnegative integer. (Contributed by Mario Carneiro, 19-Apr-2015.) (Revised by AV, 6-Sep-2021.)
|- ; 1 0 e. NN0
Theorem	10re 9466	The number 10 is real. (Contributed by NM, 5-Feb-2007.) (Revised by AV, 8-Sep-2021.)
|- ; 1 0 e. RR
Theorem	decnncl 9467	Closure for a numeral. (Contributed by Mario Carneiro, 17-Apr-2015.) (Revised by AV, 6-Sep-2021.)
|- A e. NN0   &    |- B e. NN   =>    |- ; A B e. NN
Theorem	dec0u 9468	Add a zero in the units place. (Contributed by Mario Carneiro, 17-Apr-2015.) (Revised by AV, 6-Sep-2021.)
|- A e. NN0   =>    |- (; 1 0 x. A ) = ; A 0
Theorem	dec0h 9469	Add a zero in the higher places. (Contributed by Mario Carneiro, 17-Apr-2015.) (Revised by AV, 6-Sep-2021.)
|- A e. NN0   =>    |- A = ; 0 A
Theorem	numnncl2 9470	Closure for a decimal integer (zero units place). (Contributed by Mario Carneiro, 9-Mar-2015.)
|- T e. NN   &    |- A e. NN   =>    |- ( ( T x. A ) + 0 ) e. NN
Theorem	decnncl2 9471	Closure for a decimal integer (zero units place). (Contributed by Mario Carneiro, 17-Apr-2015.) (Revised by AV, 6-Sep-2021.)
|- A e. NN   =>    |- ; A 0 e. NN
Theorem	numlt 9472	Comparing two decimal integers (equal higher places). (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN   &    |- A e. NN0   &    |- B e. NN0   &    |- C e. NN   &    |- B < C   =>    |- ( ( T x. A ) + B ) < ( ( T x. A ) + C )
Theorem	numltc 9473	Comparing two decimal integers (unequal higher places). (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN   &    |- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- C < T   &    |- A < B   =>    |- ( ( T x. A ) + C ) < ( ( T x. B ) + D )
Theorem	le9lt10 9474	A "decimal digit" (i.e. a nonnegative integer less than or equal to 9) is less then 10. (Contributed by AV, 8-Sep-2021.)
|- A e. NN0   &    |- A <_ 9   =>    |- A < ; 1 0
Theorem	declt 9475	Comparing two decimal integers (equal higher places). (Contributed by Mario Carneiro, 17-Apr-2015.) (Revised by AV, 6-Sep-2021.)
|- A e. NN0   &    |- B e. NN0   &    |- C e. NN   &    |- B < C   =>    |- ; A B < ; A C
Theorem	decltc 9476	Comparing two decimal integers (unequal higher places). (Contributed by Mario Carneiro, 18-Feb-2014.) (Revised by AV, 6-Sep-2021.)
|- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- C < ; 1 0   &    |- A < B   =>    |- ; A C < ; B D
Theorem	declth 9477	Comparing two decimal integers (unequal higher places). (Contributed by AV, 8-Sep-2021.)
|- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- C <_ 9   &    |- A < B   =>    |- ; A C < ; B D
Theorem	decsuc 9478	The successor of a decimal integer (no carry). (Contributed by Mario Carneiro, 17-Apr-2015.) (Revised by AV, 6-Sep-2021.)
|- A e. NN0   &    |- B e. NN0   &    |- ( B + 1 ) = C   &    |- N = ; A B   =>    |- ( N + 1 ) = ; A C
Theorem	3declth 9479	Comparing two decimal integers with three "digits" (unequal higher places). (Contributed by AV, 8-Sep-2021.)
|- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- E e. NN0   &    |- F e. NN0   &    |- A < B   &    |- C <_ 9   &    |- E <_ 9   =>    |- ;; A C E < ;; B D F
Theorem	3decltc 9480	Comparing two decimal integers with three "digits" (unequal higher places). (Contributed by AV, 15-Jun-2021.) (Revised by AV, 6-Sep-2021.)
|- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- E e. NN0   &    |- F e. NN0   &    |- A < B   &    |- C < ; 1 0   &    |- E < ; 1 0   =>    |- ;; A C E < ;; B D F
Theorem	decle 9481	Comparing two decimal integers (equal higher places). (Contributed by AV, 17-Aug-2021.) (Revised by AV, 8-Sep-2021.)
|- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- B <_ C   =>    |- ; A B <_ ; A C
Theorem	decleh 9482	Comparing two decimal integers (unequal higher places). (Contributed by AV, 17-Aug-2021.) (Revised by AV, 8-Sep-2021.)
|- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- C <_ 9   &    |- A < B   =>    |- ; A C <_ ; B D
Theorem	declei 9483	Comparing a digit to a decimal integer. (Contributed by AV, 17-Aug-2021.)
|- A e. NN   &    |- B e. NN0   &    |- C e. NN0   &    |- C <_ 9   =>    |- C <_ ; A B
Theorem	numlti 9484	Comparing a digit to a decimal integer. (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN   &    |- A e. NN   &    |- B e. NN0   &    |- C e. NN0   &    |- C < T   =>    |- C < ( ( T x. A ) + B )
Theorem	declti 9485	Comparing a digit to a decimal integer. (Contributed by Mario Carneiro, 18-Feb-2014.) (Revised by AV, 6-Sep-2021.)
|- A e. NN   &    |- B e. NN0   &    |- C e. NN0   &    |- C < ; 1 0   =>    |- C < ; A B
Theorem	decltdi 9486	Comparing a digit to a decimal integer. (Contributed by AV, 8-Sep-2021.)
|- A e. NN   &    |- B e. NN0   &    |- C e. NN0   &    |- C <_ 9   =>    |- C < ; A B
Theorem	numsucc 9487	The successor of a decimal integer (with carry). (Contributed by Mario Carneiro, 18-Feb-2014.)
|- Y e. NN0   &    |- T = ( Y + 1 )   &    |- A e. NN0   &    |- ( A + 1 ) = B   &    |- N = ( ( T x. A ) + Y )   =>    |- ( N + 1 ) = ( ( T x. B ) + 0 )
Theorem	decsucc 9488	The successor of a decimal integer (with carry). (Contributed by Mario Carneiro, 18-Feb-2014.) (Revised by AV, 6-Sep-2021.)
|- A e. NN0   &    |- ( A + 1 ) = B   &    |- N = ; A 9   =>    |- ( N + 1 ) = ; B 0
Theorem	1e0p1 9489	The successor of zero. (Contributed by Mario Carneiro, 18-Feb-2014.)
|- 1 = ( 0 + 1 )
Theorem	dec10p 9490	Ten plus an integer. (Contributed by Mario Carneiro, 19-Apr-2015.) (Revised by AV, 6-Sep-2021.)
|- (; 1 0 + A ) = ; 1 A
Theorem	numma 9491	Perform a multiply-add of two decimal integers M and N against a fixed multiplicand P (no carry). (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN0   &    |- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- M = ( ( T x. A ) + B )   &    |- N = ( ( T x. C ) + D )   &    |- P e. NN0   &    |- ( ( A x. P ) + C ) = E   &    |- ( ( B x. P ) + D ) = F   =>    |- ( ( M x. P ) + N ) = ( ( T x. E ) + F )
Theorem	nummac 9492	Perform a multiply-add of two decimal integers M and N against a fixed multiplicand P (with carry). (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN0   &    |- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- M = ( ( T x. A ) + B )   &    |- N = ( ( T x. C ) + D )   &    |- P e. NN0   &    |- F e. NN0   &    |- G e. NN0   &    |- ( ( A x. P ) + ( C + G ) ) = E   &    |- ( ( B x. P ) + D ) = ( ( T x. G ) + F )   =>    |- ( ( M x. P ) + N ) = ( ( T x. E ) + F )
Theorem	numma2c 9493	Perform a multiply-add of two decimal integers M and N against a fixed multiplicand P (with carry). (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN0   &    |- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- M = ( ( T x. A ) + B )   &    |- N = ( ( T x. C ) + D )   &    |- P e. NN0   &    |- F e. NN0   &    |- G e. NN0   &    |- ( ( P x. A ) + ( C + G ) ) = E   &    |- ( ( P x. B ) + D ) = ( ( T x. G ) + F )   =>    |- ( ( P x. M ) + N ) = ( ( T x. E ) + F )
Theorem	numadd 9494	Add two decimal integers M and N (no carry). (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN0   &    |- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- M = ( ( T x. A ) + B )   &    |- N = ( ( T x. C ) + D )   &    |- ( A + C ) = E   &    |- ( B + D ) = F   =>    |- ( M + N ) = ( ( T x. E ) + F )
Theorem	numaddc 9495	Add two decimal integers M and N (with carry). (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN0   &    |- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- M = ( ( T x. A ) + B )   &    |- N = ( ( T x. C ) + D )   &    |- F e. NN0   &    |- ( ( A + C ) + 1 ) = E   &    |- ( B + D ) = ( ( T x. 1 ) + F )   =>    |- ( M + N ) = ( ( T x. E ) + F )
Theorem	nummul1c 9496	The product of a decimal integer with a number. (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN0   &    |- P e. NN0   &    |- A e. NN0   &    |- B e. NN0   &    |- N = ( ( T x. A ) + B )   &    |- D e. NN0   &    |- E e. NN0   &    |- ( ( A x. P ) + E ) = C   &    |- ( B x. P ) = ( ( T x. E ) + D )   =>    |- ( N x. P ) = ( ( T x. C ) + D )
Theorem	nummul2c 9497	The product of a decimal integer with a number (with carry). (Contributed by Mario Carneiro, 18-Feb-2014.)
|- T e. NN0   &    |- P e. NN0   &    |- A e. NN0   &    |- B e. NN0   &    |- N = ( ( T x. A ) + B )   &    |- D e. NN0   &    |- E e. NN0   &    |- ( ( P x. A ) + E ) = C   &    |- ( P x. B ) = ( ( T x. E ) + D )   =>    |- ( P x. N ) = ( ( T x. C ) + D )
Theorem	decma 9498	Perform a multiply-add of two numerals M and N against a fixed multiplicand P (no carry). (Contributed by Mario Carneiro, 18-Feb-2014.) (Revised by AV, 6-Sep-2021.)
|- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- M = ; A B   &    |- N = ; C D   &    |- P e. NN0   &    |- ( ( A x. P ) + C ) = E   &    |- ( ( B x. P ) + D ) = F   =>    |- ( ( M x. P ) + N ) = ; E F
Theorem	decmac 9499	Perform a multiply-add of two numerals M and N against a fixed multiplicand P (with carry). (Contributed by Mario Carneiro, 18-Feb-2014.) (Revised by AV, 6-Sep-2021.)
|- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- M = ; A B   &    |- N = ; C D   &    |- P e. NN0   &    |- F e. NN0   &    |- G e. NN0   &    |- ( ( A x. P ) + ( C + G ) ) = E   &    |- ( ( B x. P ) + D ) = ; G F   =>    |- ( ( M x. P ) + N ) = ; E F
Theorem	decma2c 9500	Perform a multiply-add of two numerals M and N against a fixed multiplier P (with carry). (Contributed by Mario Carneiro, 18-Feb-2014.) (Revised by AV, 6-Sep-2021.)
|- A e. NN0   &    |- B e. NN0   &    |- C e. NN0   &    |- D e. NN0   &    |- M = ; A B   &    |- N = ; C D   &    |- P e. NN0   &    |- F e. NN0   &    |- G e. NN0   &    |- ( ( P x. A ) + ( C + G ) ) = E   &    |- ( ( P x. B ) + D ) = ; G F   =>    |- ( ( P x. M ) + N ) = ; E F