src/HOL/OrderedGroup.thy
changeset 35060 6088dfd5f9c8
parent 35059 acbc346e5310
parent 35054 a5db9779b026
child 35061 be1e25a62ec8
child 35108 eeec2a320a77
     1.1 --- a/src/HOL/OrderedGroup.thy	Mon Feb 08 15:49:01 2010 -0800
     1.2 +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.3 @@ -1,1446 +0,0 @@
     1.4 -(*  Title:   HOL/OrderedGroup.thy
     1.5 -    Author:  Gertrud Bauer, Steven Obua, Lawrence C Paulson, Markus Wenzel, Jeremy Avigad
     1.6 -*)
     1.7 -
     1.8 -header {* Ordered Groups *}
     1.9 -
    1.10 -theory OrderedGroup
    1.11 -imports Lattices
    1.12 -uses "~~/src/Provers/Arith/abel_cancel.ML"
    1.13 -begin
    1.14 -
    1.15 -text {*
    1.16 -  The theory of partially ordered groups is taken from the books:
    1.17 -  \begin{itemize}
    1.18 -  \item \emph{Lattice Theory} by Garret Birkhoff, American Mathematical Society 1979 
    1.19 -  \item \emph{Partially Ordered Algebraic Systems}, Pergamon Press 1963
    1.20 -  \end{itemize}
    1.21 -  Most of the used notions can also be looked up in 
    1.22 -  \begin{itemize}
    1.23 -  \item \url{http://www.mathworld.com} by Eric Weisstein et. al.
    1.24 -  \item \emph{Algebra I} by van der Waerden, Springer.
    1.25 -  \end{itemize}
    1.26 -*}
    1.27 -
    1.28 -ML {*
    1.29 -structure Algebra_Simps = Named_Thms(
    1.30 -  val name = "algebra_simps"
    1.31 -  val description = "algebra simplification rules"
    1.32 -)
    1.33 -*}
    1.34 -
    1.35 -setup Algebra_Simps.setup
    1.36 -
    1.37 -text{* The rewrites accumulated in @{text algebra_simps} deal with the
    1.38 -classical algebraic structures of groups, rings and family. They simplify
    1.39 -terms by multiplying everything out (in case of a ring) and bringing sums and
    1.40 -products into a canonical form (by ordered rewriting). As a result it decides
    1.41 -group and ring equalities but also helps with inequalities.
    1.42 -
    1.43 -Of course it also works for fields, but it knows nothing about multiplicative
    1.44 -inverses or division. This is catered for by @{text field_simps}. *}
    1.45 -
    1.46 -subsection {* Semigroups and Monoids *}
    1.47 -
    1.48 -class semigroup_add = plus +
    1.49 -  assumes add_assoc [algebra_simps]: "(a + b) + c = a + (b + c)"
    1.50 -
    1.51 -sublocale semigroup_add < plus!: semigroup plus proof
    1.52 -qed (fact add_assoc)
    1.53 -
    1.54 -class ab_semigroup_add = semigroup_add +
    1.55 -  assumes add_commute [algebra_simps]: "a + b = b + a"
    1.56 -
    1.57 -sublocale ab_semigroup_add < plus!: abel_semigroup plus proof
    1.58 -qed (fact add_commute)
    1.59 -
    1.60 -context ab_semigroup_add
    1.61 -begin
    1.62 -
    1.63 -lemmas add_left_commute [algebra_simps] = plus.left_commute
    1.64 -
    1.65 -theorems add_ac = add_assoc add_commute add_left_commute
    1.66 -
    1.67 -end
    1.68 -
    1.69 -theorems add_ac = add_assoc add_commute add_left_commute
    1.70 -
    1.71 -class semigroup_mult = times +
    1.72 -  assumes mult_assoc [algebra_simps]: "(a * b) * c = a * (b * c)"
    1.73 -
    1.74 -sublocale semigroup_mult < times!: semigroup times proof
    1.75 -qed (fact mult_assoc)
    1.76 -
    1.77 -class ab_semigroup_mult = semigroup_mult +
    1.78 -  assumes mult_commute [algebra_simps]: "a * b = b * a"
    1.79 -
    1.80 -sublocale ab_semigroup_mult < times!: abel_semigroup times proof
    1.81 -qed (fact mult_commute)
    1.82 -
    1.83 -context ab_semigroup_mult
    1.84 -begin
    1.85 -
    1.86 -lemmas mult_left_commute [algebra_simps] = times.left_commute
    1.87 -
    1.88 -theorems mult_ac = mult_assoc mult_commute mult_left_commute
    1.89 -
    1.90 -end
    1.91 -
    1.92 -theorems mult_ac = mult_assoc mult_commute mult_left_commute
    1.93 -
    1.94 -class ab_semigroup_idem_mult = ab_semigroup_mult +
    1.95 -  assumes mult_idem: "x * x = x"
    1.96 -
    1.97 -sublocale ab_semigroup_idem_mult < times!: semilattice times proof
    1.98 -qed (fact mult_idem)
    1.99 -
   1.100 -context ab_semigroup_idem_mult
   1.101 -begin
   1.102 -
   1.103 -lemmas mult_left_idem = times.left_idem
   1.104 -
   1.105 -end
   1.106 -
   1.107 -class monoid_add = zero + semigroup_add +
   1.108 -  assumes add_0_left [simp]: "0 + a = a"
   1.109 -    and add_0_right [simp]: "a + 0 = a"
   1.110 -
   1.111 -lemma zero_reorient: "0 = x \<longleftrightarrow> x = 0"
   1.112 -by (rule eq_commute)
   1.113 -
   1.114 -class comm_monoid_add = zero + ab_semigroup_add +
   1.115 -  assumes add_0: "0 + a = a"
   1.116 -begin
   1.117 -
   1.118 -subclass monoid_add
   1.119 -  proof qed (insert add_0, simp_all add: add_commute)
   1.120 -
   1.121 -end
   1.122 -
   1.123 -class monoid_mult = one + semigroup_mult +
   1.124 -  assumes mult_1_left [simp]: "1 * a  = a"
   1.125 -  assumes mult_1_right [simp]: "a * 1 = a"
   1.126 -
   1.127 -lemma one_reorient: "1 = x \<longleftrightarrow> x = 1"
   1.128 -by (rule eq_commute)
   1.129 -
   1.130 -class comm_monoid_mult = one + ab_semigroup_mult +
   1.131 -  assumes mult_1: "1 * a = a"
   1.132 -begin
   1.133 -
   1.134 -subclass monoid_mult
   1.135 -  proof qed (insert mult_1, simp_all add: mult_commute)
   1.136 -
   1.137 -end
   1.138 -
   1.139 -class cancel_semigroup_add = semigroup_add +
   1.140 -  assumes add_left_imp_eq: "a + b = a + c \<Longrightarrow> b = c"
   1.141 -  assumes add_right_imp_eq: "b + a = c + a \<Longrightarrow> b = c"
   1.142 -begin
   1.143 -
   1.144 -lemma add_left_cancel [simp]:
   1.145 -  "a + b = a + c \<longleftrightarrow> b = c"
   1.146 -by (blast dest: add_left_imp_eq)
   1.147 -
   1.148 -lemma add_right_cancel [simp]:
   1.149 -  "b + a = c + a \<longleftrightarrow> b = c"
   1.150 -by (blast dest: add_right_imp_eq)
   1.151 -
   1.152 -end
   1.153 -
   1.154 -class cancel_ab_semigroup_add = ab_semigroup_add +
   1.155 -  assumes add_imp_eq: "a + b = a + c \<Longrightarrow> b = c"
   1.156 -begin
   1.157 -
   1.158 -subclass cancel_semigroup_add
   1.159 -proof
   1.160 -  fix a b c :: 'a
   1.161 -  assume "a + b = a + c" 
   1.162 -  then show "b = c" by (rule add_imp_eq)
   1.163 -next
   1.164 -  fix a b c :: 'a
   1.165 -  assume "b + a = c + a"
   1.166 -  then have "a + b = a + c" by (simp only: add_commute)
   1.167 -  then show "b = c" by (rule add_imp_eq)
   1.168 -qed
   1.169 -
   1.170 -end
   1.171 -
   1.172 -class cancel_comm_monoid_add = cancel_ab_semigroup_add + comm_monoid_add
   1.173 -
   1.174 -
   1.175 -subsection {* Groups *}
   1.176 -
   1.177 -class group_add = minus + uminus + monoid_add +
   1.178 -  assumes left_minus [simp]: "- a + a = 0"
   1.179 -  assumes diff_minus: "a - b = a + (- b)"
   1.180 -begin
   1.181 -
   1.182 -lemma minus_unique:
   1.183 -  assumes "a + b = 0" shows "- a = b"
   1.184 -proof -
   1.185 -  have "- a = - a + (a + b)" using assms by simp
   1.186 -  also have "\<dots> = b" by (simp add: add_assoc [symmetric])
   1.187 -  finally show ?thesis .
   1.188 -qed
   1.189 -
   1.190 -lemmas equals_zero_I = minus_unique (* legacy name *)
   1.191 -
   1.192 -lemma minus_zero [simp]: "- 0 = 0"
   1.193 -proof -
   1.194 -  have "0 + 0 = 0" by (rule add_0_right)
   1.195 -  thus "- 0 = 0" by (rule minus_unique)
   1.196 -qed
   1.197 -
   1.198 -lemma minus_minus [simp]: "- (- a) = a"
   1.199 -proof -
   1.200 -  have "- a + a = 0" by (rule left_minus)
   1.201 -  thus "- (- a) = a" by (rule minus_unique)
   1.202 -qed
   1.203 -
   1.204 -lemma right_minus [simp]: "a + - a = 0"
   1.205 -proof -
   1.206 -  have "a + - a = - (- a) + - a" by simp
   1.207 -  also have "\<dots> = 0" by (rule left_minus)
   1.208 -  finally show ?thesis .
   1.209 -qed
   1.210 -
   1.211 -lemma minus_add_cancel: "- a + (a + b) = b"
   1.212 -by (simp add: add_assoc [symmetric])
   1.213 -
   1.214 -lemma add_minus_cancel: "a + (- a + b) = b"
   1.215 -by (simp add: add_assoc [symmetric])
   1.216 -
   1.217 -lemma minus_add: "- (a + b) = - b + - a"
   1.218 -proof -
   1.219 -  have "(a + b) + (- b + - a) = 0"
   1.220 -    by (simp add: add_assoc add_minus_cancel)
   1.221 -  thus "- (a + b) = - b + - a"
   1.222 -    by (rule minus_unique)
   1.223 -qed
   1.224 -
   1.225 -lemma right_minus_eq: "a - b = 0 \<longleftrightarrow> a = b"
   1.226 -proof
   1.227 -  assume "a - b = 0"
   1.228 -  have "a = (a - b) + b" by (simp add:diff_minus add_assoc)
   1.229 -  also have "\<dots> = b" using `a - b = 0` by simp
   1.230 -  finally show "a = b" .
   1.231 -next
   1.232 -  assume "a = b" thus "a - b = 0" by (simp add: diff_minus)
   1.233 -qed
   1.234 -
   1.235 -lemma diff_self [simp]: "a - a = 0"
   1.236 -by (simp add: diff_minus)
   1.237 -
   1.238 -lemma diff_0 [simp]: "0 - a = - a"
   1.239 -by (simp add: diff_minus)
   1.240 -
   1.241 -lemma diff_0_right [simp]: "a - 0 = a" 
   1.242 -by (simp add: diff_minus)
   1.243 -
   1.244 -lemma diff_minus_eq_add [simp]: "a - - b = a + b"
   1.245 -by (simp add: diff_minus)
   1.246 -
   1.247 -lemma neg_equal_iff_equal [simp]:
   1.248 -  "- a = - b \<longleftrightarrow> a = b" 
   1.249 -proof 
   1.250 -  assume "- a = - b"
   1.251 -  hence "- (- a) = - (- b)" by simp
   1.252 -  thus "a = b" by simp
   1.253 -next
   1.254 -  assume "a = b"
   1.255 -  thus "- a = - b" by simp
   1.256 -qed
   1.257 -
   1.258 -lemma neg_equal_0_iff_equal [simp]:
   1.259 -  "- a = 0 \<longleftrightarrow> a = 0"
   1.260 -by (subst neg_equal_iff_equal [symmetric], simp)
   1.261 -
   1.262 -lemma neg_0_equal_iff_equal [simp]:
   1.263 -  "0 = - a \<longleftrightarrow> 0 = a"
   1.264 -by (subst neg_equal_iff_equal [symmetric], simp)
   1.265 -
   1.266 -text{*The next two equations can make the simplifier loop!*}
   1.267 -
   1.268 -lemma equation_minus_iff:
   1.269 -  "a = - b \<longleftrightarrow> b = - a"
   1.270 -proof -
   1.271 -  have "- (- a) = - b \<longleftrightarrow> - a = b" by (rule neg_equal_iff_equal)
   1.272 -  thus ?thesis by (simp add: eq_commute)
   1.273 -qed
   1.274 -
   1.275 -lemma minus_equation_iff:
   1.276 -  "- a = b \<longleftrightarrow> - b = a"
   1.277 -proof -
   1.278 -  have "- a = - (- b) \<longleftrightarrow> a = -b" by (rule neg_equal_iff_equal)
   1.279 -  thus ?thesis by (simp add: eq_commute)
   1.280 -qed
   1.281 -
   1.282 -lemma diff_add_cancel: "a - b + b = a"
   1.283 -by (simp add: diff_minus add_assoc)
   1.284 -
   1.285 -lemma add_diff_cancel: "a + b - b = a"
   1.286 -by (simp add: diff_minus add_assoc)
   1.287 -
   1.288 -declare diff_minus[symmetric, algebra_simps]
   1.289 -
   1.290 -lemma eq_neg_iff_add_eq_0: "a = - b \<longleftrightarrow> a + b = 0"
   1.291 -proof
   1.292 -  assume "a = - b" then show "a + b = 0" by simp
   1.293 -next
   1.294 -  assume "a + b = 0"
   1.295 -  moreover have "a + (b + - b) = (a + b) + - b"
   1.296 -    by (simp only: add_assoc)
   1.297 -  ultimately show "a = - b" by simp
   1.298 -qed
   1.299 -
   1.300 -end
   1.301 -
   1.302 -class ab_group_add = minus + uminus + comm_monoid_add +
   1.303 -  assumes ab_left_minus: "- a + a = 0"
   1.304 -  assumes ab_diff_minus: "a - b = a + (- b)"
   1.305 -begin
   1.306 -
   1.307 -subclass group_add
   1.308 -  proof qed (simp_all add: ab_left_minus ab_diff_minus)
   1.309 -
   1.310 -subclass cancel_comm_monoid_add
   1.311 -proof
   1.312 -  fix a b c :: 'a
   1.313 -  assume "a + b = a + c"
   1.314 -  then have "- a + a + b = - a + a + c"
   1.315 -    unfolding add_assoc by simp
   1.316 -  then show "b = c" by simp
   1.317 -qed
   1.318 -
   1.319 -lemma uminus_add_conv_diff[algebra_simps]:
   1.320 -  "- a + b = b - a"
   1.321 -by (simp add:diff_minus add_commute)
   1.322 -
   1.323 -lemma minus_add_distrib [simp]:
   1.324 -  "- (a + b) = - a + - b"
   1.325 -by (rule minus_unique) (simp add: add_ac)
   1.326 -
   1.327 -lemma minus_diff_eq [simp]:
   1.328 -  "- (a - b) = b - a"
   1.329 -by (simp add: diff_minus add_commute)
   1.330 -
   1.331 -lemma add_diff_eq[algebra_simps]: "a + (b - c) = (a + b) - c"
   1.332 -by (simp add: diff_minus add_ac)
   1.333 -
   1.334 -lemma diff_add_eq[algebra_simps]: "(a - b) + c = (a + c) - b"
   1.335 -by (simp add: diff_minus add_ac)
   1.336 -
   1.337 -lemma diff_eq_eq[algebra_simps]: "a - b = c \<longleftrightarrow> a = c + b"
   1.338 -by (auto simp add: diff_minus add_assoc)
   1.339 -
   1.340 -lemma eq_diff_eq[algebra_simps]: "a = c - b \<longleftrightarrow> a + b = c"
   1.341 -by (auto simp add: diff_minus add_assoc)
   1.342 -
   1.343 -lemma diff_diff_eq[algebra_simps]: "(a - b) - c = a - (b + c)"
   1.344 -by (simp add: diff_minus add_ac)
   1.345 -
   1.346 -lemma diff_diff_eq2[algebra_simps]: "a - (b - c) = (a + c) - b"
   1.347 -by (simp add: diff_minus add_ac)
   1.348 -
   1.349 -lemma eq_iff_diff_eq_0: "a = b \<longleftrightarrow> a - b = 0"
   1.350 -by (simp add: algebra_simps)
   1.351 -
   1.352 -lemma diff_eq_0_iff_eq [simp, noatp]: "a - b = 0 \<longleftrightarrow> a = b"
   1.353 -by (simp add: algebra_simps)
   1.354 -
   1.355 -end
   1.356 -
   1.357 -subsection {* (Partially) Ordered Groups *} 
   1.358 -
   1.359 -class pordered_ab_semigroup_add = order + ab_semigroup_add +
   1.360 -  assumes add_left_mono: "a \<le> b \<Longrightarrow> c + a \<le> c + b"
   1.361 -begin
   1.362 -
   1.363 -lemma add_right_mono:
   1.364 -  "a \<le> b \<Longrightarrow> a + c \<le> b + c"
   1.365 -by (simp add: add_commute [of _ c] add_left_mono)
   1.366 -
   1.367 -text {* non-strict, in both arguments *}
   1.368 -lemma add_mono:
   1.369 -  "a \<le> b \<Longrightarrow> c \<le> d \<Longrightarrow> a + c \<le> b + d"
   1.370 -  apply (erule add_right_mono [THEN order_trans])
   1.371 -  apply (simp add: add_commute add_left_mono)
   1.372 -  done
   1.373 -
   1.374 -end
   1.375 -
   1.376 -class pordered_cancel_ab_semigroup_add =
   1.377 -  pordered_ab_semigroup_add + cancel_ab_semigroup_add
   1.378 -begin
   1.379 -
   1.380 -lemma add_strict_left_mono:
   1.381 -  "a < b \<Longrightarrow> c + a < c + b"
   1.382 -by (auto simp add: less_le add_left_mono)
   1.383 -
   1.384 -lemma add_strict_right_mono:
   1.385 -  "a < b \<Longrightarrow> a + c < b + c"
   1.386 -by (simp add: add_commute [of _ c] add_strict_left_mono)
   1.387 -
   1.388 -text{*Strict monotonicity in both arguments*}
   1.389 -lemma add_strict_mono:
   1.390 -  "a < b \<Longrightarrow> c < d \<Longrightarrow> a + c < b + d"
   1.391 -apply (erule add_strict_right_mono [THEN less_trans])
   1.392 -apply (erule add_strict_left_mono)
   1.393 -done
   1.394 -
   1.395 -lemma add_less_le_mono:
   1.396 -  "a < b \<Longrightarrow> c \<le> d \<Longrightarrow> a + c < b + d"
   1.397 -apply (erule add_strict_right_mono [THEN less_le_trans])
   1.398 -apply (erule add_left_mono)
   1.399 -done
   1.400 -
   1.401 -lemma add_le_less_mono:
   1.402 -  "a \<le> b \<Longrightarrow> c < d \<Longrightarrow> a + c < b + d"
   1.403 -apply (erule add_right_mono [THEN le_less_trans])
   1.404 -apply (erule add_strict_left_mono) 
   1.405 -done
   1.406 -
   1.407 -end
   1.408 -
   1.409 -class pordered_ab_semigroup_add_imp_le =
   1.410 -  pordered_cancel_ab_semigroup_add +
   1.411 -  assumes add_le_imp_le_left: "c + a \<le> c + b \<Longrightarrow> a \<le> b"
   1.412 -begin
   1.413 -
   1.414 -lemma add_less_imp_less_left:
   1.415 -  assumes less: "c + a < c + b" shows "a < b"
   1.416 -proof -
   1.417 -  from less have le: "c + a <= c + b" by (simp add: order_le_less)
   1.418 -  have "a <= b" 
   1.419 -    apply (insert le)
   1.420 -    apply (drule add_le_imp_le_left)
   1.421 -    by (insert le, drule add_le_imp_le_left, assumption)
   1.422 -  moreover have "a \<noteq> b"
   1.423 -  proof (rule ccontr)
   1.424 -    assume "~(a \<noteq> b)"
   1.425 -    then have "a = b" by simp
   1.426 -    then have "c + a = c + b" by simp
   1.427 -    with less show "False"by simp
   1.428 -  qed
   1.429 -  ultimately show "a < b" by (simp add: order_le_less)
   1.430 -qed
   1.431 -
   1.432 -lemma add_less_imp_less_right:
   1.433 -  "a + c < b + c \<Longrightarrow> a < b"
   1.434 -apply (rule add_less_imp_less_left [of c])
   1.435 -apply (simp add: add_commute)  
   1.436 -done
   1.437 -
   1.438 -lemma add_less_cancel_left [simp]:
   1.439 -  "c + a < c + b \<longleftrightarrow> a < b"
   1.440 -by (blast intro: add_less_imp_less_left add_strict_left_mono) 
   1.441 -
   1.442 -lemma add_less_cancel_right [simp]:
   1.443 -  "a + c < b + c \<longleftrightarrow> a < b"
   1.444 -by (blast intro: add_less_imp_less_right add_strict_right_mono)
   1.445 -
   1.446 -lemma add_le_cancel_left [simp]:
   1.447 -  "c + a \<le> c + b \<longleftrightarrow> a \<le> b"
   1.448 -by (auto, drule add_le_imp_le_left, simp_all add: add_left_mono) 
   1.449 -
   1.450 -lemma add_le_cancel_right [simp]:
   1.451 -  "a + c \<le> b + c \<longleftrightarrow> a \<le> b"
   1.452 -by (simp add: add_commute [of a c] add_commute [of b c])
   1.453 -
   1.454 -lemma add_le_imp_le_right:
   1.455 -  "a + c \<le> b + c \<Longrightarrow> a \<le> b"
   1.456 -by simp
   1.457 -
   1.458 -lemma max_add_distrib_left:
   1.459 -  "max x y + z = max (x + z) (y + z)"
   1.460 -  unfolding max_def by auto
   1.461 -
   1.462 -lemma min_add_distrib_left:
   1.463 -  "min x y + z = min (x + z) (y + z)"
   1.464 -  unfolding min_def by auto
   1.465 -
   1.466 -end
   1.467 -
   1.468 -subsection {* Support for reasoning about signs *}
   1.469 -
   1.470 -class pordered_comm_monoid_add =
   1.471 -  pordered_cancel_ab_semigroup_add + comm_monoid_add
   1.472 -begin
   1.473 -
   1.474 -lemma add_pos_nonneg:
   1.475 -  assumes "0 < a" and "0 \<le> b" shows "0 < a + b"
   1.476 -proof -
   1.477 -  have "0 + 0 < a + b" 
   1.478 -    using assms by (rule add_less_le_mono)
   1.479 -  then show ?thesis by simp
   1.480 -qed
   1.481 -
   1.482 -lemma add_pos_pos:
   1.483 -  assumes "0 < a" and "0 < b" shows "0 < a + b"
   1.484 -by (rule add_pos_nonneg) (insert assms, auto)
   1.485 -
   1.486 -lemma add_nonneg_pos:
   1.487 -  assumes "0 \<le> a" and "0 < b" shows "0 < a + b"
   1.488 -proof -
   1.489 -  have "0 + 0 < a + b" 
   1.490 -    using assms by (rule add_le_less_mono)
   1.491 -  then show ?thesis by simp
   1.492 -qed
   1.493 -
   1.494 -lemma add_nonneg_nonneg:
   1.495 -  assumes "0 \<le> a" and "0 \<le> b" shows "0 \<le> a + b"
   1.496 -proof -
   1.497 -  have "0 + 0 \<le> a + b" 
   1.498 -    using assms by (rule add_mono)
   1.499 -  then show ?thesis by simp
   1.500 -qed
   1.501 -
   1.502 -lemma add_neg_nonpos:
   1.503 -  assumes "a < 0" and "b \<le> 0" shows "a + b < 0"
   1.504 -proof -
   1.505 -  have "a + b < 0 + 0"
   1.506 -    using assms by (rule add_less_le_mono)
   1.507 -  then show ?thesis by simp
   1.508 -qed
   1.509 -
   1.510 -lemma add_neg_neg: 
   1.511 -  assumes "a < 0" and "b < 0" shows "a + b < 0"
   1.512 -by (rule add_neg_nonpos) (insert assms, auto)
   1.513 -
   1.514 -lemma add_nonpos_neg:
   1.515 -  assumes "a \<le> 0" and "b < 0" shows "a + b < 0"
   1.516 -proof -
   1.517 -  have "a + b < 0 + 0"
   1.518 -    using assms by (rule add_le_less_mono)
   1.519 -  then show ?thesis by simp
   1.520 -qed
   1.521 -
   1.522 -lemma add_nonpos_nonpos:
   1.523 -  assumes "a \<le> 0" and "b \<le> 0" shows "a + b \<le> 0"
   1.524 -proof -
   1.525 -  have "a + b \<le> 0 + 0"
   1.526 -    using assms by (rule add_mono)
   1.527 -  then show ?thesis by simp
   1.528 -qed
   1.529 -
   1.530 -lemmas add_sign_intros =
   1.531 -  add_pos_nonneg add_pos_pos add_nonneg_pos add_nonneg_nonneg
   1.532 -  add_neg_nonpos add_neg_neg add_nonpos_neg add_nonpos_nonpos
   1.533 -
   1.534 -lemma add_nonneg_eq_0_iff:
   1.535 -  assumes x: "0 \<le> x" and y: "0 \<le> y"
   1.536 -  shows "x + y = 0 \<longleftrightarrow> x = 0 \<and> y = 0"
   1.537 -proof (intro iffI conjI)
   1.538 -  have "x = x + 0" by simp
   1.539 -  also have "x + 0 \<le> x + y" using y by (rule add_left_mono)
   1.540 -  also assume "x + y = 0"
   1.541 -  also have "0 \<le> x" using x .
   1.542 -  finally show "x = 0" .
   1.543 -next
   1.544 -  have "y = 0 + y" by simp
   1.545 -  also have "0 + y \<le> x + y" using x by (rule add_right_mono)
   1.546 -  also assume "x + y = 0"
   1.547 -  also have "0 \<le> y" using y .
   1.548 -  finally show "y = 0" .
   1.549 -next
   1.550 -  assume "x = 0 \<and> y = 0"
   1.551 -  then show "x + y = 0" by simp
   1.552 -qed
   1.553 -
   1.554 -end
   1.555 -
   1.556 -class pordered_ab_group_add =
   1.557 -  ab_group_add + pordered_ab_semigroup_add
   1.558 -begin
   1.559 -
   1.560 -subclass pordered_cancel_ab_semigroup_add ..
   1.561 -
   1.562 -subclass pordered_ab_semigroup_add_imp_le
   1.563 -proof
   1.564 -  fix a b c :: 'a
   1.565 -  assume "c + a \<le> c + b"
   1.566 -  hence "(-c) + (c + a) \<le> (-c) + (c + b)" by (rule add_left_mono)
   1.567 -  hence "((-c) + c) + a \<le> ((-c) + c) + b" by (simp only: add_assoc)
   1.568 -  thus "a \<le> b" by simp
   1.569 -qed
   1.570 -
   1.571 -subclass pordered_comm_monoid_add ..
   1.572 -
   1.573 -lemma max_diff_distrib_left:
   1.574 -  shows "max x y - z = max (x - z) (y - z)"
   1.575 -by (simp add: diff_minus, rule max_add_distrib_left) 
   1.576 -
   1.577 -lemma min_diff_distrib_left:
   1.578 -  shows "min x y - z = min (x - z) (y - z)"
   1.579 -by (simp add: diff_minus, rule min_add_distrib_left) 
   1.580 -
   1.581 -lemma le_imp_neg_le:
   1.582 -  assumes "a \<le> b" shows "-b \<le> -a"
   1.583 -proof -
   1.584 -  have "-a+a \<le> -a+b" using `a \<le> b` by (rule add_left_mono) 
   1.585 -  hence "0 \<le> -a+b" by simp
   1.586 -  hence "0 + (-b) \<le> (-a + b) + (-b)" by (rule add_right_mono) 
   1.587 -  thus ?thesis by (simp add: add_assoc)
   1.588 -qed
   1.589 -
   1.590 -lemma neg_le_iff_le [simp]: "- b \<le> - a \<longleftrightarrow> a \<le> b"
   1.591 -proof 
   1.592 -  assume "- b \<le> - a"
   1.593 -  hence "- (- a) \<le> - (- b)" by (rule le_imp_neg_le)
   1.594 -  thus "a\<le>b" by simp
   1.595 -next
   1.596 -  assume "a\<le>b"
   1.597 -  thus "-b \<le> -a" by (rule le_imp_neg_le)
   1.598 -qed
   1.599 -
   1.600 -lemma neg_le_0_iff_le [simp]: "- a \<le> 0 \<longleftrightarrow> 0 \<le> a"
   1.601 -by (subst neg_le_iff_le [symmetric], simp)
   1.602 -
   1.603 -lemma neg_0_le_iff_le [simp]: "0 \<le> - a \<longleftrightarrow> a \<le> 0"
   1.604 -by (subst neg_le_iff_le [symmetric], simp)
   1.605 -
   1.606 -lemma neg_less_iff_less [simp]: "- b < - a \<longleftrightarrow> a < b"
   1.607 -by (force simp add: less_le) 
   1.608 -
   1.609 -lemma neg_less_0_iff_less [simp]: "- a < 0 \<longleftrightarrow> 0 < a"
   1.610 -by (subst neg_less_iff_less [symmetric], simp)
   1.611 -
   1.612 -lemma neg_0_less_iff_less [simp]: "0 < - a \<longleftrightarrow> a < 0"
   1.613 -by (subst neg_less_iff_less [symmetric], simp)
   1.614 -
   1.615 -text{*The next several equations can make the simplifier loop!*}
   1.616 -
   1.617 -lemma less_minus_iff: "a < - b \<longleftrightarrow> b < - a"
   1.618 -proof -
   1.619 -  have "(- (-a) < - b) = (b < - a)" by (rule neg_less_iff_less)
   1.620 -  thus ?thesis by simp
   1.621 -qed
   1.622 -
   1.623 -lemma minus_less_iff: "- a < b \<longleftrightarrow> - b < a"
   1.624 -proof -
   1.625 -  have "(- a < - (-b)) = (- b < a)" by (rule neg_less_iff_less)
   1.626 -  thus ?thesis by simp
   1.627 -qed
   1.628 -
   1.629 -lemma le_minus_iff: "a \<le> - b \<longleftrightarrow> b \<le> - a"
   1.630 -proof -
   1.631 -  have mm: "!! a (b::'a). (-(-a)) < -b \<Longrightarrow> -(-b) < -a" by (simp only: minus_less_iff)
   1.632 -  have "(- (- a) <= -b) = (b <= - a)" 
   1.633 -    apply (auto simp only: le_less)
   1.634 -    apply (drule mm)
   1.635 -    apply (simp_all)
   1.636 -    apply (drule mm[simplified], assumption)
   1.637 -    done
   1.638 -  then show ?thesis by simp
   1.639 -qed
   1.640 -
   1.641 -lemma minus_le_iff: "- a \<le> b \<longleftrightarrow> - b \<le> a"
   1.642 -by (auto simp add: le_less minus_less_iff)
   1.643 -
   1.644 -lemma less_iff_diff_less_0: "a < b \<longleftrightarrow> a - b < 0"
   1.645 -proof -
   1.646 -  have  "(a < b) = (a + (- b) < b + (-b))"  
   1.647 -    by (simp only: add_less_cancel_right)
   1.648 -  also have "... =  (a - b < 0)" by (simp add: diff_minus)
   1.649 -  finally show ?thesis .
   1.650 -qed
   1.651 -
   1.652 -lemma diff_less_eq[algebra_simps]: "a - b < c \<longleftrightarrow> a < c + b"
   1.653 -apply (subst less_iff_diff_less_0 [of a])
   1.654 -apply (rule less_iff_diff_less_0 [of _ c, THEN ssubst])
   1.655 -apply (simp add: diff_minus add_ac)
   1.656 -done
   1.657 -
   1.658 -lemma less_diff_eq[algebra_simps]: "a < c - b \<longleftrightarrow> a + b < c"
   1.659 -apply (subst less_iff_diff_less_0 [of "plus a b"])
   1.660 -apply (subst less_iff_diff_less_0 [of a])
   1.661 -apply (simp add: diff_minus add_ac)
   1.662 -done
   1.663 -
   1.664 -lemma diff_le_eq[algebra_simps]: "a - b \<le> c \<longleftrightarrow> a \<le> c + b"
   1.665 -by (auto simp add: le_less diff_less_eq diff_add_cancel add_diff_cancel)
   1.666 -
   1.667 -lemma le_diff_eq[algebra_simps]: "a \<le> c - b \<longleftrightarrow> a + b \<le> c"
   1.668 -by (auto simp add: le_less less_diff_eq diff_add_cancel add_diff_cancel)
   1.669 -
   1.670 -lemma le_iff_diff_le_0: "a \<le> b \<longleftrightarrow> a - b \<le> 0"
   1.671 -by (simp add: algebra_simps)
   1.672 -
   1.673 -text{*Legacy - use @{text algebra_simps} *}
   1.674 -lemmas group_simps[noatp] = algebra_simps
   1.675 -
   1.676 -end
   1.677 -
   1.678 -text{*Legacy - use @{text algebra_simps} *}
   1.679 -lemmas group_simps[noatp] = algebra_simps
   1.680 -
   1.681 -class ordered_ab_semigroup_add =
   1.682 -  linorder + pordered_ab_semigroup_add
   1.683 -
   1.684 -class ordered_cancel_ab_semigroup_add =
   1.685 -  linorder + pordered_cancel_ab_semigroup_add
   1.686 -begin
   1.687 -
   1.688 -subclass ordered_ab_semigroup_add ..
   1.689 -
   1.690 -subclass pordered_ab_semigroup_add_imp_le
   1.691 -proof
   1.692 -  fix a b c :: 'a
   1.693 -  assume le: "c + a <= c + b"  
   1.694 -  show "a <= b"
   1.695 -  proof (rule ccontr)
   1.696 -    assume w: "~ a \<le> b"
   1.697 -    hence "b <= a" by (simp add: linorder_not_le)
   1.698 -    hence le2: "c + b <= c + a" by (rule add_left_mono)
   1.699 -    have "a = b" 
   1.700 -      apply (insert le)
   1.701 -      apply (insert le2)
   1.702 -      apply (drule antisym, simp_all)
   1.703 -      done
   1.704 -    with w show False 
   1.705 -      by (simp add: linorder_not_le [symmetric])
   1.706 -  qed
   1.707 -qed
   1.708 -
   1.709 -end
   1.710 -
   1.711 -class ordered_ab_group_add =
   1.712 -  linorder + pordered_ab_group_add
   1.713 -begin
   1.714 -
   1.715 -subclass ordered_cancel_ab_semigroup_add ..
   1.716 -
   1.717 -lemma neg_less_eq_nonneg:
   1.718 -  "- a \<le> a \<longleftrightarrow> 0 \<le> a"
   1.719 -proof
   1.720 -  assume A: "- a \<le> a" show "0 \<le> a"
   1.721 -  proof (rule classical)
   1.722 -    assume "\<not> 0 \<le> a"
   1.723 -    then have "a < 0" by auto
   1.724 -    with A have "- a < 0" by (rule le_less_trans)
   1.725 -    then show ?thesis by auto
   1.726 -  qed
   1.727 -next
   1.728 -  assume A: "0 \<le> a" show "- a \<le> a"
   1.729 -  proof (rule order_trans)
   1.730 -    show "- a \<le> 0" using A by (simp add: minus_le_iff)
   1.731 -  next
   1.732 -    show "0 \<le> a" using A .
   1.733 -  qed
   1.734 -qed
   1.735 -  
   1.736 -lemma less_eq_neg_nonpos:
   1.737 -  "a \<le> - a \<longleftrightarrow> a \<le> 0"
   1.738 -proof
   1.739 -  assume A: "a \<le> - a" show "a \<le> 0"
   1.740 -  proof (rule classical)
   1.741 -    assume "\<not> a \<le> 0"
   1.742 -    then have "0 < a" by auto
   1.743 -    then have "0 < - a" using A by (rule less_le_trans)
   1.744 -    then show ?thesis by auto
   1.745 -  qed
   1.746 -next
   1.747 -  assume A: "a \<le> 0" show "a \<le> - a"
   1.748 -  proof (rule order_trans)
   1.749 -    show "0 \<le> - a" using A by (simp add: minus_le_iff)
   1.750 -  next
   1.751 -    show "a \<le> 0" using A .
   1.752 -  qed
   1.753 -qed
   1.754 -
   1.755 -lemma equal_neg_zero:
   1.756 -  "a = - a \<longleftrightarrow> a = 0"
   1.757 -proof
   1.758 -  assume "a = 0" then show "a = - a" by simp
   1.759 -next
   1.760 -  assume A: "a = - a" show "a = 0"
   1.761 -  proof (cases "0 \<le> a")
   1.762 -    case True with A have "0 \<le> - a" by auto
   1.763 -    with le_minus_iff have "a \<le> 0" by simp
   1.764 -    with True show ?thesis by (auto intro: order_trans)
   1.765 -  next
   1.766 -    case False then have B: "a \<le> 0" by auto
   1.767 -    with A have "- a \<le> 0" by auto
   1.768 -    with B show ?thesis by (auto intro: order_trans)
   1.769 -  qed
   1.770 -qed
   1.771 -
   1.772 -lemma neg_equal_zero:
   1.773 -  "- a = a \<longleftrightarrow> a = 0"
   1.774 -  unfolding equal_neg_zero [symmetric] by auto
   1.775 -
   1.776 -end
   1.777 -
   1.778 --- {* FIXME localize the following *}
   1.779 -
   1.780 -lemma add_increasing:
   1.781 -  fixes c :: "'a::{pordered_ab_semigroup_add_imp_le, comm_monoid_add}"
   1.782 -  shows  "[|0\<le>a; b\<le>c|] ==> b \<le> a + c"
   1.783 -by (insert add_mono [of 0 a b c], simp)
   1.784 -
   1.785 -lemma add_increasing2:
   1.786 -  fixes c :: "'a::{pordered_ab_semigroup_add_imp_le, comm_monoid_add}"
   1.787 -  shows  "[|0\<le>c; b\<le>a|] ==> b \<le> a + c"
   1.788 -by (simp add:add_increasing add_commute[of a])
   1.789 -
   1.790 -lemma add_strict_increasing:
   1.791 -  fixes c :: "'a::{pordered_ab_semigroup_add_imp_le, comm_monoid_add}"
   1.792 -  shows "[|0<a; b\<le>c|] ==> b < a + c"
   1.793 -by (insert add_less_le_mono [of 0 a b c], simp)
   1.794 -
   1.795 -lemma add_strict_increasing2:
   1.796 -  fixes c :: "'a::{pordered_ab_semigroup_add_imp_le, comm_monoid_add}"
   1.797 -  shows "[|0\<le>a; b<c|] ==> b < a + c"
   1.798 -by (insert add_le_less_mono [of 0 a b c], simp)
   1.799 -
   1.800 -
   1.801 -class pordered_ab_group_add_abs = pordered_ab_group_add + abs +
   1.802 -  assumes abs_ge_zero [simp]: "\<bar>a\<bar> \<ge> 0"
   1.803 -    and abs_ge_self: "a \<le> \<bar>a\<bar>"
   1.804 -    and abs_leI: "a \<le> b \<Longrightarrow> - a \<le> b \<Longrightarrow> \<bar>a\<bar> \<le> b"
   1.805 -    and abs_minus_cancel [simp]: "\<bar>-a\<bar> = \<bar>a\<bar>"
   1.806 -    and abs_triangle_ineq: "\<bar>a + b\<bar> \<le> \<bar>a\<bar> + \<bar>b\<bar>"
   1.807 -begin
   1.808 -
   1.809 -lemma abs_minus_le_zero: "- \<bar>a\<bar> \<le> 0"
   1.810 -  unfolding neg_le_0_iff_le by simp
   1.811 -
   1.812 -lemma abs_of_nonneg [simp]:
   1.813 -  assumes nonneg: "0 \<le> a" shows "\<bar>a\<bar> = a"
   1.814 -proof (rule antisym)
   1.815 -  from nonneg le_imp_neg_le have "- a \<le> 0" by simp
   1.816 -  from this nonneg have "- a \<le> a" by (rule order_trans)
   1.817 -  then show "\<bar>a\<bar> \<le> a" by (auto intro: abs_leI)
   1.818 -qed (rule abs_ge_self)
   1.819 -
   1.820 -lemma abs_idempotent [simp]: "\<bar>\<bar>a\<bar>\<bar> = \<bar>a\<bar>"
   1.821 -by (rule antisym)
   1.822 -   (auto intro!: abs_ge_self abs_leI order_trans [of "uminus (abs a)" zero "abs a"])
   1.823 -
   1.824 -lemma abs_eq_0 [simp]: "\<bar>a\<bar> = 0 \<longleftrightarrow> a = 0"
   1.825 -proof -
   1.826 -  have "\<bar>a\<bar> = 0 \<Longrightarrow> a = 0"
   1.827 -  proof (rule antisym)
   1.828 -    assume zero: "\<bar>a\<bar> = 0"
   1.829 -    with abs_ge_self show "a \<le> 0" by auto
   1.830 -    from zero have "\<bar>-a\<bar> = 0" by simp
   1.831 -    with abs_ge_self [of "uminus a"] have "- a \<le> 0" by auto
   1.832 -    with neg_le_0_iff_le show "0 \<le> a" by auto
   1.833 -  qed
   1.834 -  then show ?thesis by auto
   1.835 -qed
   1.836 -
   1.837 -lemma abs_zero [simp]: "\<bar>0\<bar> = 0"
   1.838 -by simp
   1.839 -
   1.840 -lemma abs_0_eq [simp, noatp]: "0 = \<bar>a\<bar> \<longleftrightarrow> a = 0"
   1.841 -proof -
   1.842 -  have "0 = \<bar>a\<bar> \<longleftrightarrow> \<bar>a\<bar> = 0" by (simp only: eq_ac)
   1.843 -  thus ?thesis by simp
   1.844 -qed
   1.845 -
   1.846 -lemma abs_le_zero_iff [simp]: "\<bar>a\<bar> \<le> 0 \<longleftrightarrow> a = 0" 
   1.847 -proof
   1.848 -  assume "\<bar>a\<bar> \<le> 0"
   1.849 -  then have "\<bar>a\<bar> = 0" by (rule antisym) simp
   1.850 -  thus "a = 0" by simp
   1.851 -next
   1.852 -  assume "a = 0"
   1.853 -  thus "\<bar>a\<bar> \<le> 0" by simp
   1.854 -qed
   1.855 -
   1.856 -lemma zero_less_abs_iff [simp]: "0 < \<bar>a\<bar> \<longleftrightarrow> a \<noteq> 0"
   1.857 -by (simp add: less_le)
   1.858 -
   1.859 -lemma abs_not_less_zero [simp]: "\<not> \<bar>a\<bar> < 0"
   1.860 -proof -
   1.861 -  have a: "\<And>x y. x \<le> y \<Longrightarrow> \<not> y < x" by auto
   1.862 -  show ?thesis by (simp add: a)
   1.863 -qed
   1.864 -
   1.865 -lemma abs_ge_minus_self: "- a \<le> \<bar>a\<bar>"
   1.866 -proof -
   1.867 -  have "- a \<le> \<bar>-a\<bar>" by (rule abs_ge_self)
   1.868 -  then show ?thesis by simp
   1.869 -qed
   1.870 -
   1.871 -lemma abs_minus_commute: 
   1.872 -  "\<bar>a - b\<bar> = \<bar>b - a\<bar>"
   1.873 -proof -
   1.874 -  have "\<bar>a - b\<bar> = \<bar>- (a - b)\<bar>" by (simp only: abs_minus_cancel)
   1.875 -  also have "... = \<bar>b - a\<bar>" by simp
   1.876 -  finally show ?thesis .
   1.877 -qed
   1.878 -
   1.879 -lemma abs_of_pos: "0 < a \<Longrightarrow> \<bar>a\<bar> = a"
   1.880 -by (rule abs_of_nonneg, rule less_imp_le)
   1.881 -
   1.882 -lemma abs_of_nonpos [simp]:
   1.883 -  assumes "a \<le> 0" shows "\<bar>a\<bar> = - a"
   1.884 -proof -
   1.885 -  let ?b = "- a"
   1.886 -  have "- ?b \<le> 0 \<Longrightarrow> \<bar>- ?b\<bar> = - (- ?b)"
   1.887 -  unfolding abs_minus_cancel [of "?b"]
   1.888 -  unfolding neg_le_0_iff_le [of "?b"]
   1.889 -  unfolding minus_minus by (erule abs_of_nonneg)
   1.890 -  then show ?thesis using assms by auto
   1.891 -qed
   1.892 -  
   1.893 -lemma abs_of_neg: "a < 0 \<Longrightarrow> \<bar>a\<bar> = - a"
   1.894 -by (rule abs_of_nonpos, rule less_imp_le)
   1.895 -
   1.896 -lemma abs_le_D1: "\<bar>a\<bar> \<le> b \<Longrightarrow> a \<le> b"
   1.897 -by (insert abs_ge_self, blast intro: order_trans)
   1.898 -
   1.899 -lemma abs_le_D2: "\<bar>a\<bar> \<le> b \<Longrightarrow> - a \<le> b"
   1.900 -by (insert abs_le_D1 [of "uminus a"], simp)
   1.901 -
   1.902 -lemma abs_le_iff: "\<bar>a\<bar> \<le> b \<longleftrightarrow> a \<le> b \<and> - a \<le> b"
   1.903 -by (blast intro: abs_leI dest: abs_le_D1 abs_le_D2)
   1.904 -
   1.905 -lemma abs_triangle_ineq2: "\<bar>a\<bar> - \<bar>b\<bar> \<le> \<bar>a - b\<bar>"
   1.906 -  apply (simp add: algebra_simps)
   1.907 -  apply (subgoal_tac "abs a = abs (plus b (minus a b))")
   1.908 -  apply (erule ssubst)
   1.909 -  apply (rule abs_triangle_ineq)
   1.910 -  apply (rule arg_cong[of _ _ abs])
   1.911 -  apply (simp add: algebra_simps)
   1.912 -done
   1.913 -
   1.914 -lemma abs_triangle_ineq3: "\<bar>\<bar>a\<bar> - \<bar>b\<bar>\<bar> \<le> \<bar>a - b\<bar>"
   1.915 -  apply (subst abs_le_iff)
   1.916 -  apply auto
   1.917 -  apply (rule abs_triangle_ineq2)
   1.918 -  apply (subst abs_minus_commute)
   1.919 -  apply (rule abs_triangle_ineq2)
   1.920 -done
   1.921 -
   1.922 -lemma abs_triangle_ineq4: "\<bar>a - b\<bar> \<le> \<bar>a\<bar> + \<bar>b\<bar>"
   1.923 -proof -
   1.924 -  have "abs(a - b) = abs(a + - b)" by (subst diff_minus, rule refl)
   1.925 -  also have "... <= abs a + abs (- b)" by (rule abs_triangle_ineq)
   1.926 -  finally show ?thesis by simp
   1.927 -qed
   1.928 -
   1.929 -lemma abs_diff_triangle_ineq: "\<bar>a + b - (c + d)\<bar> \<le> \<bar>a - c\<bar> + \<bar>b - d\<bar>"
   1.930 -proof -
   1.931 -  have "\<bar>a + b - (c+d)\<bar> = \<bar>(a-c) + (b-d)\<bar>" by (simp add: diff_minus add_ac)
   1.932 -  also have "... \<le> \<bar>a-c\<bar> + \<bar>b-d\<bar>" by (rule abs_triangle_ineq)
   1.933 -  finally show ?thesis .
   1.934 -qed
   1.935 -
   1.936 -lemma abs_add_abs [simp]:
   1.937 -  "\<bar>\<bar>a\<bar> + \<bar>b\<bar>\<bar> = \<bar>a\<bar> + \<bar>b\<bar>" (is "?L = ?R")
   1.938 -proof (rule antisym)
   1.939 -  show "?L \<ge> ?R" by(rule abs_ge_self)
   1.940 -next
   1.941 -  have "?L \<le> \<bar>\<bar>a\<bar>\<bar> + \<bar>\<bar>b\<bar>\<bar>" by(rule abs_triangle_ineq)
   1.942 -  also have "\<dots> = ?R" by simp
   1.943 -  finally show "?L \<le> ?R" .
   1.944 -qed
   1.945 -
   1.946 -end
   1.947 -
   1.948 -
   1.949 -subsection {* Lattice Ordered (Abelian) Groups *}
   1.950 -
   1.951 -class lordered_ab_group_add_meet = pordered_ab_group_add + lower_semilattice
   1.952 -begin
   1.953 -
   1.954 -lemma add_inf_distrib_left:
   1.955 -  "a + inf b c = inf (a + b) (a + c)"
   1.956 -apply (rule antisym)
   1.957 -apply (simp_all add: le_infI)
   1.958 -apply (rule add_le_imp_le_left [of "uminus a"])
   1.959 -apply (simp only: add_assoc [symmetric], simp)
   1.960 -apply rule
   1.961 -apply (rule add_le_imp_le_left[of "a"], simp only: add_assoc[symmetric], simp)+
   1.962 -done
   1.963 -
   1.964 -lemma add_inf_distrib_right:
   1.965 -  "inf a b + c = inf (a + c) (b + c)"
   1.966 -proof -
   1.967 -  have "c + inf a b = inf (c+a) (c+b)" by (simp add: add_inf_distrib_left)
   1.968 -  thus ?thesis by (simp add: add_commute)
   1.969 -qed
   1.970 -
   1.971 -end
   1.972 -
   1.973 -class lordered_ab_group_add_join = pordered_ab_group_add + upper_semilattice
   1.974 -begin
   1.975 -
   1.976 -lemma add_sup_distrib_left:
   1.977 -  "a + sup b c = sup (a + b) (a + c)" 
   1.978 -apply (rule antisym)
   1.979 -apply (rule add_le_imp_le_left [of "uminus a"])
   1.980 -apply (simp only: add_assoc[symmetric], simp)
   1.981 -apply rule
   1.982 -apply (rule add_le_imp_le_left [of "a"], simp only: add_assoc[symmetric], simp)+
   1.983 -apply (rule le_supI)
   1.984 -apply (simp_all)
   1.985 -done
   1.986 -
   1.987 -lemma add_sup_distrib_right:
   1.988 -  "sup a b + c = sup (a+c) (b+c)"
   1.989 -proof -
   1.990 -  have "c + sup a b = sup (c+a) (c+b)" by (simp add: add_sup_distrib_left)
   1.991 -  thus ?thesis by (simp add: add_commute)
   1.992 -qed
   1.993 -
   1.994 -end
   1.995 -
   1.996 -class lordered_ab_group_add = pordered_ab_group_add + lattice
   1.997 -begin
   1.998 -
   1.999 -subclass lordered_ab_group_add_meet ..
  1.1000 -subclass lordered_ab_group_add_join ..
  1.1001 -
  1.1002 -lemmas add_sup_inf_distribs = add_inf_distrib_right add_inf_distrib_left add_sup_distrib_right add_sup_distrib_left
  1.1003 -
  1.1004 -lemma inf_eq_neg_sup: "inf a b = - sup (-a) (-b)"
  1.1005 -proof (rule inf_unique)
  1.1006 -  fix a b :: 'a
  1.1007 -  show "- sup (-a) (-b) \<le> a"
  1.1008 -    by (rule add_le_imp_le_right [of _ "sup (uminus a) (uminus b)"])
  1.1009 -      (simp, simp add: add_sup_distrib_left)
  1.1010 -next
  1.1011 -  fix a b :: 'a
  1.1012 -  show "- sup (-a) (-b) \<le> b"
  1.1013 -    by (rule add_le_imp_le_right [of _ "sup (uminus a) (uminus b)"])
  1.1014 -      (simp, simp add: add_sup_distrib_left)
  1.1015 -next
  1.1016 -  fix a b c :: 'a
  1.1017 -  assume "a \<le> b" "a \<le> c"
  1.1018 -  then show "a \<le> - sup (-b) (-c)" by (subst neg_le_iff_le [symmetric])
  1.1019 -    (simp add: le_supI)
  1.1020 -qed
  1.1021 -  
  1.1022 -lemma sup_eq_neg_inf: "sup a b = - inf (-a) (-b)"
  1.1023 -proof (rule sup_unique)
  1.1024 -  fix a b :: 'a
  1.1025 -  show "a \<le> - inf (-a) (-b)"
  1.1026 -    by (rule add_le_imp_le_right [of _ "inf (uminus a) (uminus b)"])
  1.1027 -      (simp, simp add: add_inf_distrib_left)
  1.1028 -next
  1.1029 -  fix a b :: 'a
  1.1030 -  show "b \<le> - inf (-a) (-b)"
  1.1031 -    by (rule add_le_imp_le_right [of _ "inf (uminus a) (uminus b)"])
  1.1032 -      (simp, simp add: add_inf_distrib_left)
  1.1033 -next
  1.1034 -  fix a b c :: 'a
  1.1035 -  assume "a \<le> c" "b \<le> c"
  1.1036 -  then show "- inf (-a) (-b) \<le> c" by (subst neg_le_iff_le [symmetric])
  1.1037 -    (simp add: le_infI)
  1.1038 -qed
  1.1039 -
  1.1040 -lemma neg_inf_eq_sup: "- inf a b = sup (-a) (-b)"
  1.1041 -by (simp add: inf_eq_neg_sup)
  1.1042 -
  1.1043 -lemma neg_sup_eq_inf: "- sup a b = inf (-a) (-b)"
  1.1044 -by (simp add: sup_eq_neg_inf)
  1.1045 -
  1.1046 -lemma add_eq_inf_sup: "a + b = sup a b + inf a b"
  1.1047 -proof -
  1.1048 -  have "0 = - inf 0 (a-b) + inf (a-b) 0" by (simp add: inf_commute)
  1.1049 -  hence "0 = sup 0 (b-a) + inf (a-b) 0" by (simp add: inf_eq_neg_sup)
  1.1050 -  hence "0 = (-a + sup a b) + (inf a b + (-b))"
  1.1051 -    by (simp add: add_sup_distrib_left add_inf_distrib_right)
  1.1052 -       (simp add: algebra_simps)
  1.1053 -  thus ?thesis by (simp add: algebra_simps)
  1.1054 -qed
  1.1055 -
  1.1056 -subsection {* Positive Part, Negative Part, Absolute Value *}
  1.1057 -
  1.1058 -definition
  1.1059 -  nprt :: "'a \<Rightarrow> 'a" where
  1.1060 -  "nprt x = inf x 0"
  1.1061 -
  1.1062 -definition
  1.1063 -  pprt :: "'a \<Rightarrow> 'a" where
  1.1064 -  "pprt x = sup x 0"
  1.1065 -
  1.1066 -lemma pprt_neg: "pprt (- x) = - nprt x"
  1.1067 -proof -
  1.1068 -  have "sup (- x) 0 = sup (- x) (- 0)" unfolding minus_zero ..
  1.1069 -  also have "\<dots> = - inf x 0" unfolding neg_inf_eq_sup ..
  1.1070 -  finally have "sup (- x) 0 = - inf x 0" .
  1.1071 -  then show ?thesis unfolding pprt_def nprt_def .
  1.1072 -qed
  1.1073 -
  1.1074 -lemma nprt_neg: "nprt (- x) = - pprt x"
  1.1075 -proof -
  1.1076 -  from pprt_neg have "pprt (- (- x)) = - nprt (- x)" .
  1.1077 -  then have "pprt x = - nprt (- x)" by simp
  1.1078 -  then show ?thesis by simp
  1.1079 -qed
  1.1080 -
  1.1081 -lemma prts: "a = pprt a + nprt a"
  1.1082 -by (simp add: pprt_def nprt_def add_eq_inf_sup[symmetric])
  1.1083 -
  1.1084 -lemma zero_le_pprt[simp]: "0 \<le> pprt a"
  1.1085 -by (simp add: pprt_def)
  1.1086 -
  1.1087 -lemma nprt_le_zero[simp]: "nprt a \<le> 0"
  1.1088 -by (simp add: nprt_def)
  1.1089 -
  1.1090 -lemma le_eq_neg: "a \<le> - b \<longleftrightarrow> a + b \<le> 0" (is "?l = ?r")
  1.1091 -proof -
  1.1092 -  have a: "?l \<longrightarrow> ?r"
  1.1093 -    apply (auto)
  1.1094 -    apply (rule add_le_imp_le_right[of _ "uminus b" _])
  1.1095 -    apply (simp add: add_assoc)
  1.1096 -    done
  1.1097 -  have b: "?r \<longrightarrow> ?l"
  1.1098 -    apply (auto)
  1.1099 -    apply (rule add_le_imp_le_right[of _ "b" _])
  1.1100 -    apply (simp)
  1.1101 -    done
  1.1102 -  from a b show ?thesis by blast
  1.1103 -qed
  1.1104 -
  1.1105 -lemma pprt_0[simp]: "pprt 0 = 0" by (simp add: pprt_def)
  1.1106 -lemma nprt_0[simp]: "nprt 0 = 0" by (simp add: nprt_def)
  1.1107 -
  1.1108 -lemma pprt_eq_id [simp, noatp]: "0 \<le> x \<Longrightarrow> pprt x = x"
  1.1109 -  by (simp add: pprt_def sup_aci sup_absorb1)
  1.1110 -
  1.1111 -lemma nprt_eq_id [simp, noatp]: "x \<le> 0 \<Longrightarrow> nprt x = x"
  1.1112 -  by (simp add: nprt_def inf_aci inf_absorb1)
  1.1113 -
  1.1114 -lemma pprt_eq_0 [simp, noatp]: "x \<le> 0 \<Longrightarrow> pprt x = 0"
  1.1115 -  by (simp add: pprt_def sup_aci sup_absorb2)
  1.1116 -
  1.1117 -lemma nprt_eq_0 [simp, noatp]: "0 \<le> x \<Longrightarrow> nprt x = 0"
  1.1118 -  by (simp add: nprt_def inf_aci inf_absorb2)
  1.1119 -
  1.1120 -lemma sup_0_imp_0: "sup a (- a) = 0 \<Longrightarrow> a = 0"
  1.1121 -proof -
  1.1122 -  {
  1.1123 -    fix a::'a
  1.1124 -    assume hyp: "sup a (-a) = 0"
  1.1125 -    hence "sup a (-a) + a = a" by (simp)
  1.1126 -    hence "sup (a+a) 0 = a" by (simp add: add_sup_distrib_right) 
  1.1127 -    hence "sup (a+a) 0 <= a" by (simp)
  1.1128 -    hence "0 <= a" by (blast intro: order_trans inf_sup_ord)
  1.1129 -  }
  1.1130 -  note p = this
  1.1131 -  assume hyp:"sup a (-a) = 0"
  1.1132 -  hence hyp2:"sup (-a) (-(-a)) = 0" by (simp add: sup_commute)
  1.1133 -  from p[OF hyp] p[OF hyp2] show "a = 0" by simp
  1.1134 -qed
  1.1135 -
  1.1136 -lemma inf_0_imp_0: "inf a (-a) = 0 \<Longrightarrow> a = 0"
  1.1137 -apply (simp add: inf_eq_neg_sup)
  1.1138 -apply (simp add: sup_commute)
  1.1139 -apply (erule sup_0_imp_0)
  1.1140 -done
  1.1141 -
  1.1142 -lemma inf_0_eq_0 [simp, noatp]: "inf a (- a) = 0 \<longleftrightarrow> a = 0"
  1.1143 -by (rule, erule inf_0_imp_0) simp
  1.1144 -
  1.1145 -lemma sup_0_eq_0 [simp, noatp]: "sup a (- a) = 0 \<longleftrightarrow> a = 0"
  1.1146 -by (rule, erule sup_0_imp_0) simp
  1.1147 -
  1.1148 -lemma zero_le_double_add_iff_zero_le_single_add [simp]:
  1.1149 -  "0 \<le> a + a \<longleftrightarrow> 0 \<le> a"
  1.1150 -proof
  1.1151 -  assume "0 <= a + a"
  1.1152 -  hence a:"inf (a+a) 0 = 0" by (simp add: inf_commute inf_absorb1)
  1.1153 -  have "(inf a 0)+(inf a 0) = inf (inf (a+a) 0) a" (is "?l=_")
  1.1154 -    by (simp add: add_sup_inf_distribs inf_aci)
  1.1155 -  hence "?l = 0 + inf a 0" by (simp add: a, simp add: inf_commute)
  1.1156 -  hence "inf a 0 = 0" by (simp only: add_right_cancel)
  1.1157 -  then show "0 <= a" unfolding le_iff_inf by (simp add: inf_commute)
  1.1158 -next
  1.1159 -  assume a: "0 <= a"
  1.1160 -  show "0 <= a + a" by (simp add: add_mono[OF a a, simplified])
  1.1161 -qed
  1.1162 -
  1.1163 -lemma double_zero: "a + a = 0 \<longleftrightarrow> a = 0"
  1.1164 -proof
  1.1165 -  assume assm: "a + a = 0"
  1.1166 -  then have "a + a + - a = - a" by simp
  1.1167 -  then have "a + (a + - a) = - a" by (simp only: add_assoc)
  1.1168 -  then have a: "- a = a" by simp
  1.1169 -  show "a = 0" apply (rule antisym)
  1.1170 -  apply (unfold neg_le_iff_le [symmetric, of a])
  1.1171 -  unfolding a apply simp
  1.1172 -  unfolding zero_le_double_add_iff_zero_le_single_add [symmetric, of a]
  1.1173 -  unfolding assm unfolding le_less apply simp_all done
  1.1174 -next
  1.1175 -  assume "a = 0" then show "a + a = 0" by simp
  1.1176 -qed
  1.1177 -
  1.1178 -lemma zero_less_double_add_iff_zero_less_single_add:
  1.1179 -  "0 < a + a \<longleftrightarrow> 0 < a"
  1.1180 -proof (cases "a = 0")
  1.1181 -  case True then show ?thesis by auto
  1.1182 -next
  1.1183 -  case False then show ?thesis (*FIXME tune proof*)
  1.1184 -  unfolding less_le apply simp apply rule
  1.1185 -  apply clarify
  1.1186 -  apply rule
  1.1187 -  apply assumption
  1.1188 -  apply (rule notI)
  1.1189 -  unfolding double_zero [symmetric, of a] apply simp
  1.1190 -  done
  1.1191 -qed
  1.1192 -
  1.1193 -lemma double_add_le_zero_iff_single_add_le_zero [simp]:
  1.1194 -  "a + a \<le> 0 \<longleftrightarrow> a \<le> 0" 
  1.1195 -proof -
  1.1196 -  have "a + a \<le> 0 \<longleftrightarrow> 0 \<le> - (a + a)" by (subst le_minus_iff, simp)
  1.1197 -  moreover have "\<dots> \<longleftrightarrow> a \<le> 0" by (simp add: zero_le_double_add_iff_zero_le_single_add)
  1.1198 -  ultimately show ?thesis by blast
  1.1199 -qed
  1.1200 -
  1.1201 -lemma double_add_less_zero_iff_single_less_zero [simp]:
  1.1202 -  "a + a < 0 \<longleftrightarrow> a < 0"
  1.1203 -proof -
  1.1204 -  have "a + a < 0 \<longleftrightarrow> 0 < - (a + a)" by (subst less_minus_iff, simp)
  1.1205 -  moreover have "\<dots> \<longleftrightarrow> a < 0" by (simp add: zero_less_double_add_iff_zero_less_single_add)
  1.1206 -  ultimately show ?thesis by blast
  1.1207 -qed
  1.1208 -
  1.1209 -declare neg_inf_eq_sup [simp] neg_sup_eq_inf [simp]
  1.1210 -
  1.1211 -lemma le_minus_self_iff: "a \<le> - a \<longleftrightarrow> a \<le> 0"
  1.1212 -proof -
  1.1213 -  from add_le_cancel_left [of "uminus a" "plus a a" zero]
  1.1214 -  have "(a <= -a) = (a+a <= 0)" 
  1.1215 -    by (simp add: add_assoc[symmetric])
  1.1216 -  thus ?thesis by simp
  1.1217 -qed
  1.1218 -
  1.1219 -lemma minus_le_self_iff: "- a \<le> a \<longleftrightarrow> 0 \<le> a"
  1.1220 -proof -
  1.1221 -  from add_le_cancel_left [of "uminus a" zero "plus a a"]
  1.1222 -  have "(-a <= a) = (0 <= a+a)" 
  1.1223 -    by (simp add: add_assoc[symmetric])
  1.1224 -  thus ?thesis by simp
  1.1225 -qed
  1.1226 -
  1.1227 -lemma zero_le_iff_zero_nprt: "0 \<le> a \<longleftrightarrow> nprt a = 0"
  1.1228 -unfolding le_iff_inf by (simp add: nprt_def inf_commute)
  1.1229 -
  1.1230 -lemma le_zero_iff_zero_pprt: "a \<le> 0 \<longleftrightarrow> pprt a = 0"
  1.1231 -unfolding le_iff_sup by (simp add: pprt_def sup_commute)
  1.1232 -
  1.1233 -lemma le_zero_iff_pprt_id: "0 \<le> a \<longleftrightarrow> pprt a = a"
  1.1234 -unfolding le_iff_sup by (simp add: pprt_def sup_commute)
  1.1235 -
  1.1236 -lemma zero_le_iff_nprt_id: "a \<le> 0 \<longleftrightarrow> nprt a = a"
  1.1237 -unfolding le_iff_inf by (simp add: nprt_def inf_commute)
  1.1238 -
  1.1239 -lemma pprt_mono [simp, noatp]: "a \<le> b \<Longrightarrow> pprt a \<le> pprt b"
  1.1240 -unfolding le_iff_sup by (simp add: pprt_def sup_aci sup_assoc [symmetric, of a])
  1.1241 -
  1.1242 -lemma nprt_mono [simp, noatp]: "a \<le> b \<Longrightarrow> nprt a \<le> nprt b"
  1.1243 -unfolding le_iff_inf by (simp add: nprt_def inf_aci inf_assoc [symmetric, of a])
  1.1244 -
  1.1245 -end
  1.1246 -
  1.1247 -lemmas add_sup_inf_distribs = add_inf_distrib_right add_inf_distrib_left add_sup_distrib_right add_sup_distrib_left
  1.1248 -
  1.1249 -
  1.1250 -class lordered_ab_group_add_abs = lordered_ab_group_add + abs +
  1.1251 -  assumes abs_lattice: "\<bar>a\<bar> = sup a (- a)"
  1.1252 -begin
  1.1253 -
  1.1254 -lemma abs_prts: "\<bar>a\<bar> = pprt a - nprt a"
  1.1255 -proof -
  1.1256 -  have "0 \<le> \<bar>a\<bar>"
  1.1257 -  proof -
  1.1258 -    have a: "a \<le> \<bar>a\<bar>" and b: "- a \<le> \<bar>a\<bar>" by (auto simp add: abs_lattice)
  1.1259 -    show ?thesis by (rule add_mono [OF a b, simplified])
  1.1260 -  qed
  1.1261 -  then have "0 \<le> sup a (- a)" unfolding abs_lattice .
  1.1262 -  then have "sup (sup a (- a)) 0 = sup a (- a)" by (rule sup_absorb1)
  1.1263 -  then show ?thesis
  1.1264 -    by (simp add: add_sup_inf_distribs sup_aci
  1.1265 -      pprt_def nprt_def diff_minus abs_lattice)
  1.1266 -qed
  1.1267 -
  1.1268 -subclass pordered_ab_group_add_abs
  1.1269 -proof
  1.1270 -  have abs_ge_zero [simp]: "\<And>a. 0 \<le> \<bar>a\<bar>"
  1.1271 -  proof -
  1.1272 -    fix a b
  1.1273 -    have a: "a \<le> \<bar>a\<bar>" and b: "- a \<le> \<bar>a\<bar>" by (auto simp add: abs_lattice)
  1.1274 -    show "0 \<le> \<bar>a\<bar>" by (rule add_mono [OF a b, simplified])
  1.1275 -  qed
  1.1276 -  have abs_leI: "\<And>a b. a \<le> b \<Longrightarrow> - a \<le> b \<Longrightarrow> \<bar>a\<bar> \<le> b"
  1.1277 -    by (simp add: abs_lattice le_supI)
  1.1278 -  fix a b
  1.1279 -  show "0 \<le> \<bar>a\<bar>" by simp
  1.1280 -  show "a \<le> \<bar>a\<bar>"
  1.1281 -    by (auto simp add: abs_lattice)
  1.1282 -  show "\<bar>-a\<bar> = \<bar>a\<bar>"
  1.1283 -    by (simp add: abs_lattice sup_commute)
  1.1284 -  show "a \<le> b \<Longrightarrow> - a \<le> b \<Longrightarrow> \<bar>a\<bar> \<le> b" by (fact abs_leI)
  1.1285 -  show "\<bar>a + b\<bar> \<le> \<bar>a\<bar> + \<bar>b\<bar>"
  1.1286 -  proof -
  1.1287 -    have g:"abs a + abs b = sup (a+b) (sup (-a-b) (sup (-a+b) (a + (-b))))" (is "_=sup ?m ?n")
  1.1288 -      by (simp add: abs_lattice add_sup_inf_distribs sup_aci diff_minus)
  1.1289 -    have a:"a+b <= sup ?m ?n" by (simp)
  1.1290 -    have b:"-a-b <= ?n" by (simp) 
  1.1291 -    have c:"?n <= sup ?m ?n" by (simp)
  1.1292 -    from b c have d: "-a-b <= sup ?m ?n" by(rule order_trans)
  1.1293 -    have e:"-a-b = -(a+b)" by (simp add: diff_minus)
  1.1294 -    from a d e have "abs(a+b) <= sup ?m ?n" 
  1.1295 -      by (drule_tac abs_leI, auto)
  1.1296 -    with g[symmetric] show ?thesis by simp
  1.1297 -  qed
  1.1298 -qed
  1.1299 -
  1.1300 -end
  1.1301 -
  1.1302 -lemma sup_eq_if:
  1.1303 -  fixes a :: "'a\<Colon>{lordered_ab_group_add, linorder}"
  1.1304 -  shows "sup a (- a) = (if a < 0 then - a else a)"
  1.1305 -proof -
  1.1306 -  note add_le_cancel_right [of a a "- a", symmetric, simplified]
  1.1307 -  moreover note add_le_cancel_right [of "-a" a a, symmetric, simplified]
  1.1308 -  then show ?thesis by (auto simp: sup_max min_max.sup_absorb1 min_max.sup_absorb2)
  1.1309 -qed
  1.1310 -
  1.1311 -lemma abs_if_lattice:
  1.1312 -  fixes a :: "'a\<Colon>{lordered_ab_group_add_abs, linorder}"
  1.1313 -  shows "\<bar>a\<bar> = (if a < 0 then - a else a)"
  1.1314 -by auto
  1.1315 -
  1.1316 -
  1.1317 -text {* Needed for abelian cancellation simprocs: *}
  1.1318 -
  1.1319 -lemma add_cancel_21: "((x::'a::ab_group_add) + (y + z) = y + u) = (x + z = u)"
  1.1320 -apply (subst add_left_commute)
  1.1321 -apply (subst add_left_cancel)
  1.1322 -apply simp
  1.1323 -done
  1.1324 -
  1.1325 -lemma add_cancel_end: "(x + (y + z) = y) = (x = - (z::'a::ab_group_add))"
  1.1326 -apply (subst add_cancel_21[of _ _ _ 0, simplified])
  1.1327 -apply (simp add: add_right_cancel[symmetric, of "x" "-z" "z", simplified])
  1.1328 -done
  1.1329 -
  1.1330 -lemma less_eqI: "(x::'a::pordered_ab_group_add) - y = x' - y' \<Longrightarrow> (x < y) = (x' < y')"
  1.1331 -by (simp add: less_iff_diff_less_0[of x y] less_iff_diff_less_0[of x' y'])
  1.1332 -
  1.1333 -lemma le_eqI: "(x::'a::pordered_ab_group_add) - y = x' - y' \<Longrightarrow> (y <= x) = (y' <= x')"
  1.1334 -apply (simp add: le_iff_diff_le_0[of y x] le_iff_diff_le_0[of  y' x'])
  1.1335 -apply (simp add: neg_le_iff_le[symmetric, of "y-x" 0] neg_le_iff_le[symmetric, of "y'-x'" 0])
  1.1336 -done
  1.1337 -
  1.1338 -lemma eq_eqI: "(x::'a::ab_group_add) - y = x' - y' \<Longrightarrow> (x = y) = (x' = y')"
  1.1339 -by (simp only: eq_iff_diff_eq_0[of x y] eq_iff_diff_eq_0[of x' y'])
  1.1340 -
  1.1341 -lemma diff_def: "(x::'a::ab_group_add) - y == x + (-y)"
  1.1342 -by (simp add: diff_minus)
  1.1343 -
  1.1344 -lemma le_add_right_mono: 
  1.1345 -  assumes 
  1.1346 -  "a <= b + (c::'a::pordered_ab_group_add)"
  1.1347 -  "c <= d"    
  1.1348 -  shows "a <= b + d"
  1.1349 -  apply (rule_tac order_trans[where y = "b+c"])
  1.1350 -  apply (simp_all add: prems)
  1.1351 -  done
  1.1352 -
  1.1353 -lemma estimate_by_abs:
  1.1354 -  "a + b <= (c::'a::lordered_ab_group_add_abs) \<Longrightarrow> a <= c + abs b" 
  1.1355 -proof -
  1.1356 -  assume "a+b <= c"
  1.1357 -  hence 2: "a <= c+(-b)" by (simp add: algebra_simps)
  1.1358 -  have 3: "(-b) <= abs b" by (rule abs_ge_minus_self)
  1.1359 -  show ?thesis by (rule le_add_right_mono[OF 2 3])
  1.1360 -qed
  1.1361 -
  1.1362 -subsection {* Tools setup *}
  1.1363 -
  1.1364 -lemma add_mono_thms_ordered_semiring [noatp]:
  1.1365 -  fixes i j k :: "'a\<Colon>pordered_ab_semigroup_add"
  1.1366 -  shows "i \<le> j \<and> k \<le> l \<Longrightarrow> i + k \<le> j + l"
  1.1367 -    and "i = j \<and> k \<le> l \<Longrightarrow> i + k \<le> j + l"
  1.1368 -    and "i \<le> j \<and> k = l \<Longrightarrow> i + k \<le> j + l"
  1.1369 -    and "i = j \<and> k = l \<Longrightarrow> i + k = j + l"
  1.1370 -by (rule add_mono, clarify+)+
  1.1371 -
  1.1372 -lemma add_mono_thms_ordered_field [noatp]:
  1.1373 -  fixes i j k :: "'a\<Colon>pordered_cancel_ab_semigroup_add"
  1.1374 -  shows "i < j \<and> k = l \<Longrightarrow> i + k < j + l"
  1.1375 -    and "i = j \<and> k < l \<Longrightarrow> i + k < j + l"
  1.1376 -    and "i < j \<and> k \<le> l \<Longrightarrow> i + k < j + l"
  1.1377 -    and "i \<le> j \<and> k < l \<Longrightarrow> i + k < j + l"
  1.1378 -    and "i < j \<and> k < l \<Longrightarrow> i + k < j + l"
  1.1379 -by (auto intro: add_strict_right_mono add_strict_left_mono
  1.1380 -  add_less_le_mono add_le_less_mono add_strict_mono)
  1.1381 -
  1.1382 -text{*Simplification of @{term "x-y < 0"}, etc.*}
  1.1383 -lemmas diff_less_0_iff_less [simp, noatp] = less_iff_diff_less_0 [symmetric]
  1.1384 -lemmas diff_le_0_iff_le [simp, noatp] = le_iff_diff_le_0 [symmetric]
  1.1385 -
  1.1386 -ML {*
  1.1387 -structure ab_group_add_cancel = Abel_Cancel
  1.1388 -(
  1.1389 -
  1.1390 -(* term order for abelian groups *)
  1.1391 -
  1.1392 -fun agrp_ord (Const (a, _)) = find_index (fn a' => a = a')
  1.1393 -      [@{const_name Algebras.zero}, @{const_name Algebras.plus},
  1.1394 -        @{const_name Algebras.uminus}, @{const_name Algebras.minus}]
  1.1395 -  | agrp_ord _ = ~1;
  1.1396 -
  1.1397 -fun termless_agrp (a, b) = (TermOrd.term_lpo agrp_ord (a, b) = LESS);
  1.1398 -
  1.1399 -local
  1.1400 -  val ac1 = mk_meta_eq @{thm add_assoc};
  1.1401 -  val ac2 = mk_meta_eq @{thm add_commute};
  1.1402 -  val ac3 = mk_meta_eq @{thm add_left_commute};
  1.1403 -  fun solve_add_ac thy _ (_ $ (Const (@{const_name Algebras.plus},_) $ _ $ _) $ _) =
  1.1404 -        SOME ac1
  1.1405 -    | solve_add_ac thy _ (_ $ x $ (Const (@{const_name Algebras.plus},_) $ y $ z)) =
  1.1406 -        if termless_agrp (y, x) then SOME ac3 else NONE
  1.1407 -    | solve_add_ac thy _ (_ $ x $ y) =
  1.1408 -        if termless_agrp (y, x) then SOME ac2 else NONE
  1.1409 -    | solve_add_ac thy _ _ = NONE
  1.1410 -in
  1.1411 -  val add_ac_proc = Simplifier.simproc @{theory}
  1.1412 -    "add_ac_proc" ["x + y::'a::ab_semigroup_add"] solve_add_ac;
  1.1413 -end;
  1.1414 -
  1.1415 -val eq_reflection = @{thm eq_reflection};
  1.1416 -  
  1.1417 -val T = @{typ "'a::ab_group_add"};
  1.1418 -
  1.1419 -val cancel_ss = HOL_basic_ss settermless termless_agrp
  1.1420 -  addsimprocs [add_ac_proc] addsimps
  1.1421 -  [@{thm add_0_left}, @{thm add_0_right}, @{thm diff_def},
  1.1422 -   @{thm minus_add_distrib}, @{thm minus_minus}, @{thm minus_zero},
  1.1423 -   @{thm right_minus}, @{thm left_minus}, @{thm add_minus_cancel},
  1.1424 -   @{thm minus_add_cancel}];
  1.1425 -
  1.1426 -val sum_pats = [@{cterm "x + y::'a::ab_group_add"}, @{cterm "x - y::'a::ab_group_add"}];
  1.1427 -  
  1.1428 -val eqI_rules = [@{thm less_eqI}, @{thm le_eqI}, @{thm eq_eqI}];
  1.1429 -
  1.1430 -val dest_eqI = 
  1.1431 -  fst o HOLogic.dest_bin "op =" HOLogic.boolT o HOLogic.dest_Trueprop o concl_of;
  1.1432 -
  1.1433 -);
  1.1434 -*}
  1.1435 -
  1.1436 -ML {*
  1.1437 -  Addsimprocs [ab_group_add_cancel.sum_conv, ab_group_add_cancel.rel_conv];
  1.1438 -*}
  1.1439 -
  1.1440 -code_modulename SML
  1.1441 -  OrderedGroup Arith
  1.1442 -
  1.1443 -code_modulename OCaml
  1.1444 -  OrderedGroup Arith
  1.1445 -
  1.1446 -code_modulename Haskell
  1.1447 -  OrderedGroup Arith
  1.1448 -
  1.1449 -end