P. 82 of Theorem List - Intuitionistic Logic Explorer

Theorem List for Intuitionistic Logic Explorer - 8101-8200   *Has distinct variable group(s)

Type	Label	Description
Statement
Theorem	subadd 8101	Relationship between subtraction and addition. (Contributed by NM, 20-Jan-1997.) (Revised by Mario Carneiro, 21-Dec-2013.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - B ) = C <-> ( B + C ) = A ) )
Theorem	subadd2 8102	Relationship between subtraction and addition. (Contributed by Scott Fenton, 5-Jul-2013.) (Proof shortened by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - B ) = C <-> ( C + B ) = A ) )
Theorem	subsub23 8103	Swap subtrahend and result of subtraction. (Contributed by NM, 14-Dec-2007.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - B ) = C <-> ( A - C ) = B ) )
Theorem	pncan 8104	Cancellation law for subtraction. (Contributed by NM, 10-May-2004.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC ) -> ( ( A + B ) - B ) = A )
Theorem	pncan2 8105	Cancellation law for subtraction. (Contributed by NM, 17-Apr-2005.)
|- ( ( A e. CC /\ B e. CC ) -> ( ( A + B ) - A ) = B )
Theorem	pncan3 8106	Subtraction and addition of equals. (Contributed by NM, 14-Mar-2005.)
|- ( ( A e. CC /\ B e. CC ) -> ( A + ( B - A ) ) = B )
Theorem	npcan 8107	Cancellation law for subtraction. (Contributed by NM, 10-May-2004.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC ) -> ( ( A - B ) + B ) = A )
Theorem	addsubass 8108	Associative-type law for addition and subtraction. (Contributed by NM, 6-Aug-2003.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A + B ) - C ) = ( A + ( B - C ) ) )
Theorem	addsub 8109	Law for addition and subtraction. (Contributed by NM, 19-Aug-2001.) (Proof shortened by Andrew Salmon, 22-Oct-2011.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A + B ) - C ) = ( ( A - C ) + B ) )
Theorem	subadd23 8110	Commutative/associative law for addition and subtraction. (Contributed by NM, 1-Feb-2007.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - B ) + C ) = ( A + ( C - B ) ) )
Theorem	addsub12 8111	Commutative/associative law for addition and subtraction. (Contributed by NM, 8-Feb-2005.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( A + ( B - C ) ) = ( B + ( A - C ) ) )
Theorem	2addsub 8112	Law for subtraction and addition. (Contributed by NM, 20-Nov-2005.)
|- ( ( ( A e. CC /\ B e. CC ) /\ ( C e. CC /\ D e. CC ) ) -> ( ( ( A + B ) + C ) - D ) = ( ( ( A + C ) - D ) + B ) )
Theorem	addsubeq4 8113	Relation between sums and differences. (Contributed by Jeff Madsen, 17-Jun-2010.)
|- ( ( ( A e. CC /\ B e. CC ) /\ ( C e. CC /\ D e. CC ) ) -> ( ( A + B ) = ( C + D ) <-> ( C - A ) = ( B - D ) ) )
Theorem	pncan3oi 8114	Subtraction and addition of equals. Almost but not exactly the same as pncan3i 8175 and pncan 8104, this order happens often when applying "operations to both sides" so create a theorem specifically for it. A deduction version of this is available as pncand 8210. (Contributed by David A. Wheeler, 11-Oct-2018.)
|- A e. CC   &    |- B e. CC   =>    |- ( ( A + B ) - B ) = A
Theorem	mvrraddi 8115	Move RHS right addition to LHS. (Contributed by David A. Wheeler, 11-Oct-2018.)
|- B e. CC   &    |- C e. CC   &    |- A = ( B + C )   =>    |- ( A - C ) = B
Theorem	mvlladdi 8116	Move LHS left addition to RHS. (Contributed by David A. Wheeler, 11-Oct-2018.)
|- A e. CC   &    |- B e. CC   &    |- ( A + B ) = C   =>    |- B = ( C - A )
Theorem	subid 8117	Subtraction of a number from itself. (Contributed by NM, 8-Oct-1999.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( A e. CC -> ( A - A ) = 0 )
Theorem	subid1 8118	Identity law for subtraction. (Contributed by NM, 9-May-2004.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( A e. CC -> ( A - 0 ) = A )
Theorem	npncan 8119	Cancellation law for subtraction. (Contributed by NM, 8-Feb-2005.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - B ) + ( B - C ) ) = ( A - C ) )
Theorem	nppcan 8120	Cancellation law for subtraction. (Contributed by NM, 1-Sep-2005.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( ( A - B ) + C ) + B ) = ( A + C ) )
Theorem	nnpcan 8121	Cancellation law for subtraction: ((a-b)-c)+b = a-c holds for complex numbers a,b,c. (Contributed by Alexander van der Vekens, 24-Mar-2018.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( ( A - B ) - C ) + B ) = ( A - C ) )
Theorem	nppcan3 8122	Cancellation law for subtraction. (Contributed by Mario Carneiro, 14-Sep-2015.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - B ) + ( C + B ) ) = ( A + C ) )
Theorem	subcan2 8123	Cancellation law for subtraction. (Contributed by NM, 8-Feb-2005.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - C ) = ( B - C ) <-> A = B ) )
Theorem	subeq0 8124	If the difference between two numbers is zero, they are equal. (Contributed by NM, 16-Nov-1999.)
|- ( ( A e. CC /\ B e. CC ) -> ( ( A - B ) = 0 <-> A = B ) )
Theorem	npncan2 8125	Cancellation law for subtraction. (Contributed by Scott Fenton, 21-Jun-2013.)
|- ( ( A e. CC /\ B e. CC ) -> ( ( A - B ) + ( B - A ) ) = 0 )
Theorem	subsub2 8126	Law for double subtraction. (Contributed by NM, 30-Jun-2005.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( A - ( B - C ) ) = ( A + ( C - B ) ) )
Theorem	nncan 8127	Cancellation law for subtraction. (Contributed by NM, 21-Jun-2005.) (Proof shortened by Andrew Salmon, 19-Nov-2011.)
|- ( ( A e. CC /\ B e. CC ) -> ( A - ( A - B ) ) = B )
Theorem	subsub 8128	Law for double subtraction. (Contributed by NM, 13-May-2004.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( A - ( B - C ) ) = ( ( A - B ) + C ) )
Theorem	nppcan2 8129	Cancellation law for subtraction. (Contributed by NM, 29-Sep-2005.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - ( B + C ) ) + C ) = ( A - B ) )
Theorem	subsub3 8130	Law for double subtraction. (Contributed by NM, 27-Jul-2005.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( A - ( B - C ) ) = ( ( A + C ) - B ) )
Theorem	subsub4 8131	Law for double subtraction. (Contributed by NM, 19-Aug-2005.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - B ) - C ) = ( A - ( B + C ) ) )
Theorem	sub32 8132	Swap the second and third terms in a double subtraction. (Contributed by NM, 19-Aug-2005.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - B ) - C ) = ( ( A - C ) - B ) )
Theorem	nnncan 8133	Cancellation law for subtraction. (Contributed by NM, 4-Sep-2005.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - ( B - C ) ) - C ) = ( A - B ) )
Theorem	nnncan1 8134	Cancellation law for subtraction. (Contributed by NM, 8-Feb-2005.) (Proof shortened by Andrew Salmon, 19-Nov-2011.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - B ) - ( A - C ) ) = ( C - B ) )
Theorem	nnncan2 8135	Cancellation law for subtraction. (Contributed by NM, 1-Oct-2005.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - C ) - ( B - C ) ) = ( A - B ) )
Theorem	npncan3 8136	Cancellation law for subtraction. (Contributed by Scott Fenton, 23-Jun-2013.) (Proof shortened by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - B ) + ( C - A ) ) = ( C - B ) )
Theorem	pnpcan 8137	Cancellation law for mixed addition and subtraction. (Contributed by NM, 4-Mar-2005.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A + B ) - ( A + C ) ) = ( B - C ) )
Theorem	pnpcan2 8138	Cancellation law for mixed addition and subtraction. (Contributed by Scott Fenton, 9-Jun-2006.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A + C ) - ( B + C ) ) = ( A - B ) )
Theorem	pnncan 8139	Cancellation law for mixed addition and subtraction. (Contributed by NM, 30-Jun-2005.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A + B ) - ( A - C ) ) = ( B + C ) )
Theorem	ppncan 8140	Cancellation law for mixed addition and subtraction. (Contributed by NM, 30-Jun-2005.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A + B ) + ( C - B ) ) = ( A + C ) )
Theorem	addsub4 8141	Rearrangement of 4 terms in a mixed addition and subtraction. (Contributed by NM, 4-Mar-2005.)
|- ( ( ( A e. CC /\ B e. CC ) /\ ( C e. CC /\ D e. CC ) ) -> ( ( A + B ) - ( C + D ) ) = ( ( A - C ) + ( B - D ) ) )
Theorem	subadd4 8142	Rearrangement of 4 terms in a mixed addition and subtraction. (Contributed by NM, 24-Aug-2006.)
|- ( ( ( A e. CC /\ B e. CC ) /\ ( C e. CC /\ D e. CC ) ) -> ( ( A - B ) - ( C - D ) ) = ( ( A + D ) - ( B + C ) ) )
Theorem	sub4 8143	Rearrangement of 4 terms in a subtraction. (Contributed by NM, 23-Nov-2007.)
|- ( ( ( A e. CC /\ B e. CC ) /\ ( C e. CC /\ D e. CC ) ) -> ( ( A - B ) - ( C - D ) ) = ( ( A - C ) - ( B - D ) ) )
Theorem	neg0 8144	Minus 0 equals 0. (Contributed by NM, 17-Jan-1997.)
|- -u 0 = 0
Theorem	negid 8145	Addition of a number and its negative. (Contributed by NM, 14-Mar-2005.)
|- ( A e. CC -> ( A + -u A ) = 0 )
Theorem	negsub 8146	Relationship between subtraction and negative. Theorem I.3 of [Apostol] p. 18. (Contributed by NM, 21-Jan-1997.) (Proof shortened by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC ) -> ( A + -u B ) = ( A - B ) )
Theorem	subneg 8147	Relationship between subtraction and negative. (Contributed by NM, 10-May-2004.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC ) -> ( A - -u B ) = ( A + B ) )
Theorem	negneg 8148	A number is equal to the negative of its negative. Theorem I.4 of [Apostol] p. 18. (Contributed by NM, 12-Jan-2002.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( A e. CC -> -u -u A = A )
Theorem	neg11 8149	Negative is one-to-one. (Contributed by NM, 8-Feb-2005.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC ) -> ( -u A = -u B <-> A = B ) )
Theorem	negcon1 8150	Negative contraposition law. (Contributed by NM, 9-May-2004.)
|- ( ( A e. CC /\ B e. CC ) -> ( -u A = B <-> -u B = A ) )
Theorem	negcon2 8151	Negative contraposition law. (Contributed by NM, 14-Nov-2004.)
|- ( ( A e. CC /\ B e. CC ) -> ( A = -u B <-> B = -u A ) )
Theorem	negeq0 8152	A number is zero iff its negative is zero. (Contributed by NM, 12-Jul-2005.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( A e. CC -> ( A = 0 <-> -u A = 0 ) )
Theorem	subcan 8153	Cancellation law for subtraction. (Contributed by NM, 8-Feb-2005.) (Revised by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC /\ C e. CC ) -> ( ( A - B ) = ( A - C ) <-> B = C ) )
Theorem	negsubdi 8154	Distribution of negative over subtraction. (Contributed by NM, 15-Nov-2004.) (Proof shortened by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC ) -> -u ( A - B ) = ( -u A + B ) )
Theorem	negdi 8155	Distribution of negative over addition. (Contributed by NM, 10-May-2004.) (Proof shortened by Mario Carneiro, 27-May-2016.)
|- ( ( A e. CC /\ B e. CC ) -> -u ( A + B ) = ( -u A + -u B ) )
Theorem	negdi2 8156	Distribution of negative over addition. (Contributed by NM, 1-Jan-2006.)
|- ( ( A e. CC /\ B e. CC ) -> -u ( A + B ) = ( -u A - B ) )
Theorem	negsubdi2 8157	Distribution of negative over subtraction. (Contributed by NM, 4-Oct-1999.)
|- ( ( A e. CC /\ B e. CC ) -> -u ( A - B ) = ( B - A ) )
Theorem	neg2sub 8158	Relationship between subtraction and negative. (Contributed by Paul Chapman, 8-Oct-2007.)
|- ( ( A e. CC /\ B e. CC ) -> ( -u A - -u B ) = ( B - A ) )
Theorem	renegcl 8159	Closure law for negative of reals. (Contributed by NM, 20-Jan-1997.)
|- ( A e. RR -> -u A e. RR )
Theorem	renegcli 8160	Closure law for negative of reals. (Note: this inference proof style and the deduction theorem usage in renegcl 8159 is deprecated, but is retained for its demonstration value.) (Contributed by NM, 17-Jan-1997.) (Proof shortened by Andrew Salmon, 22-Oct-2011.)
|- A e. RR   =>    |- -u A e. RR
Theorem	resubcli 8161	Closure law for subtraction of reals. (Contributed by NM, 17-Jan-1997.) (Revised by Mario Carneiro, 27-May-2016.)
|- A e. RR   &    |- B e. RR   =>    |- ( A - B ) e. RR
Theorem	resubcl 8162	Closure law for subtraction of reals. (Contributed by NM, 20-Jan-1997.)
|- ( ( A e. RR /\ B e. RR ) -> ( A - B ) e. RR )
Theorem	negreb 8163	The negative of a real is real. (Contributed by NM, 11-Aug-1999.) (Revised by Mario Carneiro, 14-Jul-2014.)
|- ( A e. CC -> ( -u A e. RR <-> A e. RR ) )
Theorem	peano2cnm 8164	"Reverse" second Peano postulate analog for complex numbers: A complex number minus 1 is a complex number. (Contributed by Alexander van der Vekens, 18-Mar-2018.)
|- ( N e. CC -> ( N - 1 ) e. CC )
Theorem	peano2rem 8165	"Reverse" second Peano postulate analog for reals. (Contributed by NM, 6-Feb-2007.)
|- ( N e. RR -> ( N - 1 ) e. RR )
Theorem	negcli 8166	Closure law for negative. (Contributed by NM, 26-Nov-1994.)
|- A e. CC   =>    |- -u A e. CC
Theorem	negidi 8167	Addition of a number and its negative. (Contributed by NM, 26-Nov-1994.)
|- A e. CC   =>    |- ( A + -u A ) = 0
Theorem	negnegi 8168	A number is equal to the negative of its negative. Theorem I.4 of [Apostol] p. 18. (Contributed by NM, 8-Feb-1995.) (Proof shortened by Andrew Salmon, 22-Oct-2011.)
|- A e. CC   =>    |- -u -u A = A
Theorem	subidi 8169	Subtraction of a number from itself. (Contributed by NM, 26-Nov-1994.)
|- A e. CC   =>    |- ( A - A ) = 0
Theorem	subid1i 8170	Identity law for subtraction. (Contributed by NM, 29-May-1999.)
|- A e. CC   =>    |- ( A - 0 ) = A
Theorem	negne0bi 8171	A number is nonzero iff its negative is nonzero. (Contributed by NM, 10-Aug-1999.)
|- A e. CC   =>    |- ( A =/= 0 <-> -u A =/= 0 )
Theorem	negrebi 8172	The negative of a real is real. (Contributed by NM, 11-Aug-1999.)
|- A e. CC   =>    |- ( -u A e. RR <-> A e. RR )
Theorem	negne0i 8173	The negative of a nonzero number is nonzero. (Contributed by NM, 30-Jul-2004.)
|- A e. CC   &    |- A =/= 0   =>    |- -u A =/= 0
Theorem	subcli 8174	Closure law for subtraction. (Contributed by NM, 26-Nov-1994.) (Revised by Mario Carneiro, 21-Dec-2013.)
|- A e. CC   &    |- B e. CC   =>    |- ( A - B ) e. CC
Theorem	pncan3i 8175	Subtraction and addition of equals. (Contributed by NM, 26-Nov-1994.)
|- A e. CC   &    |- B e. CC   =>    |- ( A + ( B - A ) ) = B
Theorem	negsubi 8176	Relationship between subtraction and negative. Theorem I.3 of [Apostol] p. 18. (Contributed by NM, 26-Nov-1994.) (Proof shortened by Andrew Salmon, 22-Oct-2011.)
|- A e. CC   &    |- B e. CC   =>    |- ( A + -u B ) = ( A - B )
Theorem	subnegi 8177	Relationship between subtraction and negative. (Contributed by NM, 1-Dec-2005.)
|- A e. CC   &    |- B e. CC   =>    |- ( A - -u B ) = ( A + B )
Theorem	subeq0i 8178	If the difference between two numbers is zero, they are equal. (Contributed by NM, 8-May-1999.)
|- A e. CC   &    |- B e. CC   =>    |- ( ( A - B ) = 0 <-> A = B )
Theorem	neg11i 8179	Negative is one-to-one. (Contributed by NM, 1-Aug-1999.)
|- A e. CC   &    |- B e. CC   =>    |- ( -u A = -u B <-> A = B )
Theorem	negcon1i 8180	Negative contraposition law. (Contributed by NM, 25-Aug-1999.)
|- A e. CC   &    |- B e. CC   =>    |- ( -u A = B <-> -u B = A )
Theorem	negcon2i 8181	Negative contraposition law. (Contributed by NM, 25-Aug-1999.)
|- A e. CC   &    |- B e. CC   =>    |- ( A = -u B <-> B = -u A )
Theorem	negdii 8182	Distribution of negative over addition. (Contributed by NM, 28-Jul-1999.) (Proof shortened by Andrew Salmon, 19-Nov-2011.)
|- A e. CC   &    |- B e. CC   =>    |- -u ( A + B ) = ( -u A + -u B )
Theorem	negsubdii 8183	Distribution of negative over subtraction. (Contributed by NM, 6-Aug-1999.)
|- A e. CC   &    |- B e. CC   =>    |- -u ( A - B ) = ( -u A + B )
Theorem	negsubdi2i 8184	Distribution of negative over subtraction. (Contributed by NM, 1-Oct-1999.)
|- A e. CC   &    |- B e. CC   =>    |- -u ( A - B ) = ( B - A )
Theorem	subaddi 8185	Relationship between subtraction and addition. (Contributed by NM, 26-Nov-1994.) (Revised by Mario Carneiro, 21-Dec-2013.)
|- A e. CC   &    |- B e. CC   &    |- C e. CC   =>    |- ( ( A - B ) = C <-> ( B + C ) = A )
Theorem	subadd2i 8186	Relationship between subtraction and addition. (Contributed by NM, 15-Dec-2006.)
|- A e. CC   &    |- B e. CC   &    |- C e. CC   =>    |- ( ( A - B ) = C <-> ( C + B ) = A )
Theorem	subaddrii 8187	Relationship between subtraction and addition. (Contributed by NM, 16-Dec-2006.)
|- A e. CC   &    |- B e. CC   &    |- C e. CC   &    |- ( B + C ) = A   =>    |- ( A - B ) = C
Theorem	subsub23i 8188	Swap subtrahend and result of subtraction. (Contributed by NM, 7-Oct-1999.)
|- A e. CC   &    |- B e. CC   &    |- C e. CC   =>    |- ( ( A - B ) = C <-> ( A - C ) = B )
Theorem	addsubassi 8189	Associative-type law for subtraction and addition. (Contributed by NM, 16-Sep-1999.)
|- A e. CC   &    |- B e. CC   &    |- C e. CC   =>    |- ( ( A + B ) - C ) = ( A + ( B - C ) )
Theorem	addsubi 8190	Law for subtraction and addition. (Contributed by NM, 6-Aug-2003.)
|- A e. CC   &    |- B e. CC   &    |- C e. CC   =>    |- ( ( A + B ) - C ) = ( ( A - C ) + B )
Theorem	subcani 8191	Cancellation law for subtraction. (Contributed by NM, 8-Feb-2005.)
|- A e. CC   &    |- B e. CC   &    |- C e. CC   =>    |- ( ( A - B ) = ( A - C ) <-> B = C )
Theorem	subcan2i 8192	Cancellation law for subtraction. (Contributed by NM, 8-Feb-2005.)
|- A e. CC   &    |- B e. CC   &    |- C e. CC   =>    |- ( ( A - C ) = ( B - C ) <-> A = B )
Theorem	pnncani 8193	Cancellation law for mixed addition and subtraction. (Contributed by NM, 14-Jan-2006.)
|- A e. CC   &    |- B e. CC   &    |- C e. CC   =>    |- ( ( A + B ) - ( A - C ) ) = ( B + C )
Theorem	addsub4i 8194	Rearrangement of 4 terms in a mixed addition and subtraction. (Contributed by NM, 17-Oct-1999.)
|- A e. CC   &    |- B e. CC   &    |- C e. CC   &    |- D e. CC   =>    |- ( ( A + B ) - ( C + D ) ) = ( ( A - C ) + ( B - D ) )
Theorem	0reALT 8195	Alternate proof of 0re 7899. (Contributed by NM, 19-Feb-2005.) (Proof modification is discouraged.) (New usage is discouraged.)
|- 0 e. RR
Theorem	negcld 8196	Closure law for negative. (Contributed by Mario Carneiro, 27-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> -u A e. CC )
Theorem	subidd 8197	Subtraction of a number from itself. (Contributed by Mario Carneiro, 27-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> ( A - A ) = 0 )
Theorem	subid1d 8198	Identity law for subtraction. (Contributed by Mario Carneiro, 27-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> ( A - 0 ) = A )
Theorem	negidd 8199	Addition of a number and its negative. (Contributed by Mario Carneiro, 27-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> ( A + -u A ) = 0 )
Theorem	negnegd 8200	A number is equal to the negative of its negative. Theorem I.4 of [Apostol] p. 18. (Contributed by Mario Carneiro, 27-May-2016.)
|- ( ph -> A e. CC )   =>    |- ( ph -> -u -u A = A )